Laser control of excavating machine digging depth

Apparatus for controlling the working depth of a bucket of an excavating machine with respect to a beam of laser light which is projected at a reference height, said excavating machine having an outreach boom which is pivotally attached at one end to said machine, a downreach boom pivotally attached to the opposite end of said outreach boom, a digging bucket pivotally attached to the end of said downreach boom opposite to that to which the outreach boom is attached, and power means for producing relative pivotal movements of the pivotally interconnected elements, said apparatus comprising:

• beam sensor means mounted on said outreach boom for detecting said beam of laser light, said beam sensor means defining a plurality of individual sensor locations sized such that one of said sensor locations can be identified as sensing said beam of laser light;
• angle sensor mans for detecting the angular orientation of said downreach boom relative to vertical;
• and
• control means connected to said beam sensor means and said angle sensor means for repetitively defining one of said plurality of individual sensor locations as an on-grade sensor location as a function of the angular orientation of said downreach boom, and for comparing said on-grade sensor location tot eh sensor location having detected said beam of laser light to generate an outreach boom adjustment signal representative of the movement of said outreach boom required to move the machine such that said on-grade sensor location is illuminated by said beam of laser light and thereby maintain said bucket on-grade as said downreach boom is pivoted with respect to said outreach boom.

A method of controlling the working depth of a bucket of an excavating machine having an outreach boom which is pivotally attached at one end to said machine, a downreach boom pivotally attached to the opposite end of said outreach boom, a digging bucket pivotally attached to the end of said downreach boom opposite to that to which the outreach boom is attached, and power means for producing relative pivotal movements of the pivotally interconnected elements, said method comprising the steps of:

• projecting a beam of laser light at a reference height;
• detecting the beam of laser light by means of a beam sensor which defines a plurality of individual sensor locations sized such that only one of said sensor locations is currently sensing said beam of laser light;
• detecting the angular orientation of said downreach boom relative to vertical;
• defining one of said plurality of individual sensor locations as an on-grade sensor locations of said beam sensor as a function of the angular orientation of said downreach boom;
• and
• comparing said on-grade sensor location to the sensor location currently sensing said beam of laser light to generate an outreach boom adjustment signal representative of the movement of said outreach boom required to move the machine such that said on-grade sensor location is illuminated by said beam of laser light and thereby maintain said bucket on-grade as said downreach boom is pivoted with respect to said outreach boom.

A method of controlling the working depth of a bucket of an excavating machine with respect to a beam of laser light which is projected at a reference height, said excavating machine having an outreach boom which is pivotally attached at one end to said machine, a downreach boom pivotally attached to the opposite end of said outreach boom, a digging bucket pivotally attached to the end of said downreach boom opposite to that to which the outreach boom is attached, and power means for producing relative pivotal movements of the pivotally interconnected elements, said method comprising the steps of:

• detecting the beam of laser light by means of a beam sensor which defines a plurality of individual sensor locations sized such that only one of said sensor locations is currently sensing said beam of laser light;
• detecting the angular orientation of said downreach boom relative to vertical;
• defining one of said plurality of individual sensor locations as an on-grade sensor location of said beam sensor as a function of the angular orientation of said downreach boom;
• and
• comparing said on-grade sensor location to the sensor location currently sensing said beam of laser light to generate an outreach boom adjustment signal representative of the movement of said outreach boom required to move the machine such that said on-grade sensor location is illuminated by said beam of laser light and thereby maintain said bucket on-grade as said downreach boom is pivoted with respect to said outreach boom.