Apparatus and method for laser scanner cleaning and protection

Abstract

An air guard directs air toward a viewing window of an optoelectronic presence sensing device to reduce surface contamination thereon. The air guard may include a control valve, and possibly control circuits, to enable selective activation of the air guard. In one embodiment, the air guard includes one or more slits configured to vent pressurized air in a generally laminar (curtain like) flow in front of the window to prevent the deposition of airborne contaminants thereon. Alternatively, or additionally, the air guard may include one or more nozzles configured to vent pressurized air in directed air streams toward the window to remove surface contaminants thereon, and may include a control valve enabling selective operation in preventive, cleaning, or standby modes. Mode control may be effected by an external control system, by the presence sensing device, or by the air guard itself, which may include a timer or other control circuit.

1 . An air guard for reducing surface contamination of a viewing window of an optoelectronic presence sensing device, the air guard comprising: 
 a body section generally conforming to a contour of the viewing window;    a first chamber formed within the body section and configured to receive pressurized air from an external source; and    one or more first outlets in the body section configured to vent the pressurized air from the first chamber toward the viewing window to reduce surface contamination thereof.    
   
   
       2 . The air guard of  claim 1 , wherein the body section is integrated with a device housing of the optoelectronic presence sensing device.  
   
   
       3 . The air guard of  claim 1 , wherein the body section is affixed to a device housing of the optoelectronic presence sensing device.  
   
   
       4 . The air guard of  claim 1 , wherein the one or more first outlets comprise one or more slits in the body section configured to direct a relatively low velocity air curtain in front of at least a portion of the viewing window.  
   
   
       5 . The air guard of  claim 4 , wherein the one or more slits in the body section generally follow the contour of the viewing window.  
   
   
       6 . The air guard of  claim 1 , wherein the one or more first outlets comprise one or more spaced apart nozzles, each configured to direct a relatively high velocity air stream toward a region of the viewing window.  
   
   
       7 . The air guard of  claim 1 , wherein the body section includes a first inlet port in fluid communication with the first chamber, said first inlet port configured for coupling with a pressurized air line from the external supply.  
   
   
       8 . The air guard of  claim 1 , further comprising a control valve disposed within the body section and configured selectively to block the flow of pressurized air into the first chamber.  
   
   
       9 . The air guard of  claim 1 , further comprising a second chamber formed within the body section and configured to receive pressurized air from an external source, and one or more second outlets in the body section configured to vent the pressurized air from the second chamber toward the viewing window to reduce surface contamination thereof.  
   
   
       10 . The air guard of  claim 9 , wherein the one or more first outlets are configured as one of slits or nozzles, and wherein the one or more second outlets are configured as the other one of slits or nozzles.  
   
   
       11 . The air guard of  claim 9 , further comprising a first inlet port configured to receive pressurized air for the first chamber, and a second inlet port configured to receive pressurized air for the second chamber.  
   
   
       12 . The air guard of  claim 11 , further comprising one or more control valves configured selectively to block the flow of pressurized air into one or both the first and second chambers.  
   
   
       13 . The air guard of  claim 1 , wherein the first chamber comprises one of multiple chambers, and wherein the multiple chambers are configured such that they enable the air guard to produce different directed combinations of air flow patterns with respect to the viewing window.  
   
   
       14 . The air guard of  claim 13 , wherein the air guard includes one or more solenoids configured to selectively pressurize individual ones of the multiple chambers in desired combinations to achieve the different directed combinations of air flow patterns.  
   
   
       15 . The air guard of  claim 1 , further comprising a control circuit configured to control operation of the air guard.  
   
   
       16 . The air guard of  claim 15 , wherein the control circuit is configured to control operation of the air guard by controlling the flow of pressurized air into the first chamber based on turning a control valve on and off.  
   
   
       17 . The air guard of  claim 15 , wherein the first chamber is one of two or more chambers, and wherein pressurization of different chambers effects different air flow characteristics, and wherein the control circuit is configured to select different chambers according to a timed schedule.  
   
   
       18 . An air guard for reducing surface contamination of a viewing window of an optoelectronic presence sensing device, the air guard comprising: 
 a body section generally conforming to a contour of the viewing window;    first and second chambers formed within the body section, each configured to receive pressurized air from an external source;    one or more slits formed in the body section and configured to vent pressurized air from the first chamber in a curtain like flow in front of the viewing window; and    one or more nozzles formed in the body section and configured to vent pressurized air from the second chamber in one or more generally focused air streams directed toward the viewing window.    
   
   
       19 . The air guard of  claim 18 , wherein the body section includes at least one inlet port for receiving pressurized air for the first and second chambers, and further includes one or more control valves to control admission of pressurized air into the first and second chambers via the at least one inlet port.  
   
   
       20 . The air guard of  claim 19 , further comprising a control circuit to control actuation of the one or more control valves, such that pressurized air can be blocked from one or both the first and second chambers.  
   
   
       21 . The air guard of  claim 20 , wherein the control circuit includes a timing circuit, and wherein the control circuit is configured to actuate the one or more control valves responsive to operation of the timing circuit.  
   
   
       22 . The air guard of  claim 19 , further comprising one or more input terminals to receive valve control signals for controlling the one or more control valves.  
   
   
       23 . The air guard of  claim 18 , wherein the body section includes a first inlet port for receiving pressurized air for the first chamber and a second inlet port for receiving pressurized air into the second chamber.  
   
   
       24 . The air guard of  claim 23 , wherein the body section includes a control valve configured selectively to admit pressurized air from the first inlet port into the first chamber, and selectively to admit pressurized air from the second inlet port into the second chamber.  
   
   
       25 . The air guard of  claim 18 , wherein the air guard unit includes one or more control valves configured to permit selective operation of the air guard unit in a standby mode wherein no air flows from the air guard, in a preventive mode wherein the air guard directs a generally laminar flow in front of the viewing window by venting pressurized air from the slits to block airborne contaminates from settling on the viewing window, or in a cleaning mode wherein the air guard directs one or more air streams at the viewing window by venting air from the nozzles to remove surface contamination deposited thereon.  
   
   
       26 . An optolectronic presence sensing system comprising: 
 an optoelectronic presence sensing unit configured to detect objects by emitting optical signals through a viewing window and detecting return reflection signals therefrom; and    an air guard unit configured to direct air generally toward the viewing window of the optoelectronic presence sensing unit to reduce exterior surface contamination thereof.    
   
   
       27 . The system of  claim 26 , wherein said air guard unit includes a body section that is integrated with a housing of the optoelectronic presence sensing unit.  
   
   
       28 . The system of  claim 26 , wherein said air guard unit includes a body section that is removably attached to a housing of the optoelectronic sensing unit.  
   
   
       29 . The system of  claim 26 , wherein the optoelectronic presence sensing unit is configured to provide a control signal to the air guard unit, and wherein the air guard unit includes one or more control valves configured to control air flow from the air guard unit responsive to the control signal.  
   
   
       30 . The system of  claim 26 , wherein the air guard unit includes one or more control valves configured to permit selective operation of the air guard unit in a standby mode wherein no air flows from the air guard, in a preventive mode wherein the air guard directs a generally laminar flow in front of the viewing window to block airborne contaminates from settling on the viewing window, or in a cleaning mode wherein the air guard directs one or more air streams at the viewing window to remove surface contamination deposited thereon.  
   
   
       31 . The system of  claim 30 , wherein the optoelectronic presence sensing unit is configured to provide a control signal for controlling the one or more control valves, such that the optoelectronic presence sensing unit controls the operating mode of the air guard unit.  
   
   
       32 . The system of  claim 30 , wherein the air guard unit includes a control signal input configured to receive one or more control signals from an external controller and to couple the control signals to the one or more control valves, such that the operating mode of the air guard unit is controllable via the external controller.  
   
   
       33 . A method of maintaining a viewing window of an optoelectronic presence sensing device with respect to window contamination, the method comprising: 
 providing an air guard proximate to the viewing window;    supplying the air guard with pressurized air; and    selectively operating the air guard in a preventive mode wherein it vents the pressurized air in a generally laminar flow in front of the viewing window to prevent airborne contaminants from settling thereon, and in a cleaning mode wherein it vents the pressurized air in one or more directed air streams toward the viewing window to remove deposited surface contaminants thereon.    
   
   
       34 . The method of  claim 33 , further comprising sensing that the viewing window is contaminated and operating the air guard in the cleaning mode responsive thereto.  
   
   
       35 . The method of  claim 34 , wherein sensing that the viewing window is contaminated and operating the air guard in the cleaning mode responsive thereto comprises, at the optoelectronic presence sensing device, monitoring one or more dust detection sensors and generating a valve control signal responsive thereto, and providing the valve control signal to a control valve in the air guard that is configured to switch the air guard between the preventive mode and the cleaning mode.  
   
   
       36 . The method of  claim 33 , further comprising selectively operating the air guard in a standby mode wherein it does not vent the pressurized air.  
   
   
       37 . The method of  claim 33 , further comprising operating the air guard in the preventive and cleaning modes according to a timed schedule.  
   
   
       38 . The method of  claim 37 , further comprising including a timing circuit in the air guard or in the optoelectronic presence sensing device by which the timed schedule is maintained.  
   
   
       39 . An air guard for an optoelectronic presence sensing device, said air guard system comprising: 
 an air guard body section comprising one or more vented chambers; and    a control circuit configured to enable selective pressurization of the one or more vented chambers to effect a desired air flow pattern with respect to an optical window of the optoelectronic presence sensing device.    
   
   
       40 . The air guard of  claim 39 , wherein the control circuit comprises a valve control circuit configured to operate one or more control valves for selective pressurization of the one or more chambers responsive to one or more control signals.  
   
   
       41 . The air guard of  claim 39 , wherein the control circuit comprises timer control logic and associated valve control circuits configured to operate one or more control valves for selective pressurization of the one or more chambers responsive to a timed schedule.  
   
   
       42 . The air guard of  claim 39 , wherein the control circuit comprises a control bus interface and associated valve control circuits configured to operate one or more control valves for selective pressurization of the one or more chambers responsive to signals received through a control bus.  
   
   
       43 . The air guard of  claim 39 , wherein the control circuit comprises a portion of control logic included in the optoelectronic presence sensing device.  
   
   
       44 . The air guard of  claim 39 , wherein the control circuit resides within the air guard body section.  
   
   
       45 . The air guard of  claim 39 , further comprising one or more control valves configured to admit or block pressurized air from the one or more chambers responsive to control signals generated by the control circuit.  
   
   
       46 . The air guard of  claim 39 , wherein the control circuit is configured to enable air flow from one or more of the one or more chambers responsive to detecting contamination of the optical window.