Method and device for recognizing cross sectional external form and dimensions of a workpiece in a bandsaw machine

A method for recognizing the shape and dimensions of a workpiece which is to be cut by a band sawing machine having a saw blade and a movable vise for clamping the workpiece, and for positioning a saw blade guide of the machine, comprising the steps of:

• (a) detecting a width D of the workpiece by means of a width detector;
• (b) measuring a parameter selected from the group consisting of a contact angle .theta. and a height H of the saw blade when the saw blade contacts the workpiece prior to starting cutting, by using a detector selected form the group consisting of an angle detector and a height detector;
• (c) detecting whether a vertical side surface of the workpiece is present, by a contact sensor provided at a position selected from the group of positions consisting of positions of and along the vise;
• (d) presuming the external form and dimensions of the workpiece from data including the width D, one of the contact angle .theta. and the height H, and whether a vertical side surface is present;
• (e) detecting a parameter selected from the group consisting of a contact angle and a height of the saw blade during cutting by means of a detector selected from the group consisting of an angle detector and a height detector;
• (f) detecting positions of points defined by intersections of the saw blade and the outline of the workpiece;
• and
• (g) positioning the saw blade guide in a place which is a distance apart from the points.

An apparatus for recognizing the shape and the dimensions of a workpiece clamped by a movable vice of a band sawing machine having a saw blade so as to position a saw blade guide of the machine, comprising:

• a device for measuring a width D of the workpiece based on the movement of the vise;
• a device for measuring a parameter selected from the group consisting of a contact angle .theta. and a height H of the saw blade when the saw blade contacts the workpiece prior to starting cutting;
• a contact sensing device for detecting whether a vertical side surface of the workpiece is present, the contact sensing device being provided at a position selected from the group of positions consisting of positions on and along the vise;
• means for presuming the external form and dimensions of the workpiece from data including the width D, one of the contact angle .theta. and the height H of the saw blade and whether a vertical side surface of the workpiece is present;
• means for comparing the presumed external form and dimensions of the workpiece with data which has been previously obtained with respect to the workpiece to be cut, thereby performing a comparison;
• and
• means for positioning a saw blade guide in response to the comparison.

An automatic position adjusting device for adjusting the position of at least one saw blade guide of a band sawing machine having at least two saw blade guides and having a movable vice for clamping a workpiece to be cut by the machine, comprising:

• a device for measuring a width of the workpiece from the movement of the movable vise;
• a device for measuring a parameter selected from the group consisting of a contact angle and a height of the saw blade at a time when the saw blade contacts the workpiece and at intervals during the cutting process;
• a contact sensing device for detecting whether a vertical side surface of the workpiece is present;
• means for presuming the external form and dimensions of the workpiece, the position of the saw blade relative to the workpiece in the cutting process based on data including the width of the workpiece, each contact angle or height of the saw blade at the time when the saw blade contacts the workpiece and at intervals during the cutting, and whether a vertical side surface of the workpiece is present;
• and
• a transfer device for positioning the saw blade guide in a place determined based on the presumed data.