Line marking apparatus, system and method

Abstract

A line marking apparatus, for use in a system that includes a source of a narrow beam of radiation which extends substantially horizontally along or parallel to a line to be marked, includes a wheeled chassis and a line marking head for dispensing line marking material. The marking head is supported on the chassis for lateral movement relative thereto, which movement is controlled by a controller that includes a detector which is movable with the marking head and is positioned and directed to detect such a beam of radiation, the marking head being movable together with the detector in response to a detected beam. Lateral movement of the marking head is thereby controlled such that the head and the detector substantially follow the line to be marked irrespective of whether the chassis deviates from the line direction.

We claim: 
     
         1 . A line marking apparatus for use in a system that includes a source of a narrow beam of radiation which extends substantially horizontally along or parallel to a line to be marked, comprising:
 a chassis provided with wheels and with means for propelling the apparatus along a line to be marked;   a line marking head adapted to dispense line marking material so as to mark the line to be marked;   means supporting the line marking head such that the line marking head is movable relative to the chassis laterally on the line marking apparatus; and   means for controlling lateral movement of the line marking head and including a detector, movable with the line marking head laterally on the line marking apparatus, and positioned and directed to detect a beam of electromagnetic radiation which extends substantially horizontally along or parallel to the line to be marked, and control means for moving the line marking head with the detector in response to detection of the beam by the detector, whereby lateral movement of the line marking head with the detector relative to the chassis is controlled such that the line marking head and the detector substantially follow the line to be marked irrespective of whether the chassis deviates from the direction of such line.   
     
     
         2 . The apparatus of  claim 1 , wherein the apparatus includes a handle to facilitate pushing of the apparatus by a user. 
     
     
         3 . The apparatus of  claim 1 , wherein the apparatus includes a motor for propelling the apparatus and a seat for the user. 
     
     
         4 . The apparatus of  claim 1 , wherein the supporting means comprises an elongate housing incorporating means for moving the line marking head laterally relative to the chassis. 
     
     
         5 . The apparatus of  claim 4 , wherein line marking head support means extends from the elongate housing in a direction substantially parallel to the line to be marked. 
     
     
         6 . The apparatus of  claim 4 , wherein an actuator shaft extends laterally from the elongate housing with the line marking head extending from the actuator shaft in a direction substantially parallel to the line to be marked. 
     
     
         7 . The apparatus of  claim 1 , wherein the apparatus includes means for indicating when the beam of electromagnetic radiation is being detected by the detector. 
     
     
         8 . The apparatus of  claim 1 , wherein the apparatus includes means for warning when the line marking head is approaching the limit of its lateral movement. 
     
     
         9 . The apparatus of  claim 1 , wherein the apparatus includes means for inhibiting the marking of a line in the event the beam of electromagnetic radiation is not being detected by the detector. 
     
     
         10 . The apparatus of  claim 1 , wherein the line marking head is mounted pivotably such that the head can move upwardly and downwardly to compensate for any unevenness in the surface being marked. 
     
     
         11 . The apparatus of  claim 1 , wherein the line marking head is mounted so as to extend from the chassis substantially in the direction parallel to the line to be marked. 
     
     
         12 . The apparatus of  claim 1 , wherein the line marking head is mounted laterally of the chassis. 
     
     
         13 . The apparatus of  claim 1 , wherein the detector is provided with a shield for shielding the detector from unwanted electromagnetic radiation. 
     
     
         14 . The apparatus of  claim 1 , wherein the detector is offset laterally relative to the line marking head. 
     
     
         15 . The apparatus of  claim 1 , wherein the detector is mounted substantially in an upright plane passing through dispensing means of the line marking head. 
     
     
         16 . The apparatus of  claim 15 , wherein the detector is mounted adjacent to the dispensing means of the line marking head. 
     
     
         17 . The apparatus of  claim 1 , wherein the detector includes a plurality of sensors. 
     
     
         18 . The apparatus of  claim 17 , wherein a plurality of rows of sensors is provided. 
     
     
         19 . A line marking system comprising line marking apparatus and a source of a narrow beam of electromagnetic radiation which extends along or parallel to a line to be marked, the line marking apparatus comprising:
 a chassis provided with wheels and with means for propelling the apparatus along a line to be marked;   a line marking head adapted to dispense line marking material so as to mark the line to be marked;   means supporting the line marking head such that the line marking head is movable relative to the chassis laterally on the line marking apparatus; and   means for controlling lateral movement of the line marking head and including a detector, movable with the line marking head laterally on the line marking apparatus, and positioned and directed to detect a beam of electromagnetic radiation which extends substantially horizontally along or parallel to the line to be marked, and control means for moving the line marking head with the detector in response to detection of the beam by the detector, whereby lateral movement of the line marking head with the detector relative to the chassis is controlled such that the line marking head and the detector substantially follow the line to be marked irrespective of whether the chassis deviates from the direction of such line.   
     
     
         20 . A method of marking a line comprising:
 providing a source of a narrow beam of electromagnetic radiation and arranging the source such that the beam extends along or parallel to a line to be marked;   providing a line marking apparatus comprising:
 a chassis provided with wheels and with means for propelling the apparatus along a line to be marked; 
 a line marking head adapted to dispense line marking material so as to mark the line to be marked; 
 means supporting the line marking head such that the line marking head is movable relative to the chassis laterally on the line marking apparatus; and 
 means for controlling lateral movement of the line marking head and including a detector, movable with the line marking head laterally on the line marking apparatus, and positioned and directed to detect a beam of electromagnetic radiation which extends substantially horizontally along or parallel to the line to be marked, and control means for moving the line marking head with the detector in response to detection of the beam by the detector; 
   positioning the line marking apparatus on or adjacent to the line to be marked;   moving the line marking apparatus along the line to be marked so as to mark the line, whereby lateral movement of the line marking head with the detector relative to the chassis is controlled such that the line marking head and the detector substantially follow the line to be marked irrespective of whether the chassis deviates from the direction of such line.