Patent Publication Number: US-10315834-B2

Title: Multi-can marker stick

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of co-pending U.S. Provisional Application No. 62/305436 filed Mar. 8, 2016. 
    
    
     FIELD OF INVENTION 
     This invention relates generally to ground marking systems. This invention relates more particularly to a device that can hold at least two cans of marker paint, thus enabling marking with different colors using a single device. 
     BACKGROUND 
     It can be desirable to mark the ground surface to indicate, for example, the presence of underground utilities, the location of lot boundaries and the like. Sometimes markers are inserted into the ground that extend upward from the ground surface and may include a flag at the top end. Sometimes the ground is marked with spray paint or spray chalk, the sprayed lines indicating the approximate location of the boundary, underground pipes, wires, or cables. Different colors may be used for each utility service, such as electric, gas, telephone, water, or sewer or different boundary lines or logos. Spray paint and chalk are also commonly used to mark athletic fields with boundaries and team logos. 
     Conventionally, when marking with spray paint or chalk, the spray can is attached to a long rod that has a trigger grip on its upper end and a holster on its lower end to hold the can upside down. The devices are known as paint sticks or marker sticks. A metal finger extends from the bottom of the holster and engages the valve on the spray can. When the trigger is pulled the valve is depressed and paint sprays out the tip of the nozzle or dip tube. The desired locations are marked by walking to the desired location, aiming, and pulling the trigger. Larger areas are painted by walking the desired distance while spraying paint. If a different color paint is needed, either the can is replaced with the new desired color or a different marker stick is used. In either case, the user has to stop marking while changing paint colors. It would be desirable to make painting with different colors less cumbersome. 
     SUMMARY OF THE INVENTION 
     The present invention is a device that can hold at least two cans of spray paint or chalk, thus enabling marking with different colors using a single device. The device comprises a staff, a can holster, a grip, a trigger and a selector. The selector comprises a selector rod moveable in or alongside the staff. At one end of the selector rod is a selector knob and at the other is an engagement mechanism that engages the spray valve of each can, one can at a time. The engagement mechanism comprises a cam and a rocker arm with two opposing fingers, one to engage each spray can when selected. Optionally one or more flag holders may be attached to the staff for holding marker flags. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a marker stick of the present invention. 
         FIG. 2  is a rear view of  FIG. 1  showing the selector knob selecting can B. 
         FIG. 3  is a partial, cut-away view of the marker stick showing the engagement mechanism set to cause paint to spray from can A. 
         FIG. 4  is a partial, cut-away view of the marker stick showing the engagement mechanism engaging can A. 
         FIG. 5  is a partial, cut-away view of the marker stick showing the engagement mechanism set to cause paint to spray from can B. 
         FIG. 6  is a partial, cut-away view of the marker stick showing the engagement mechanism engaging can B. 
         FIG. 7  is a cut-away view of the grip. 
         FIG. 8  is a side view of a marker stick of the present invention with optional flag holders. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  is a side view of a marker stick of the present invention showing a staff  11 , two can holsters  12   a  and  12   b,  a grip  13 , a trigger  14 , a selector rod  15 , and a selector knob  16 . Two cans of spray paint or chalk (referred to hereinafter as just paint), first can A and second can B, can be retained within the holsters  12   a  and  12   b,  respectively. The cans are retained in the holsters with the valve pointing down so that paint is sprayed from the bottom of the device. A can holster may be of any configuration that holds the can substantially parallel to the staff  11 , such as c-shaped resilient bands or solid-wall cylinders, such as those as shown in  FIGS. 1, 4, 6, and 8 . 
     The selector rod  15  runs alongside or, preferably, inside the staff, as shown in  FIGS. 1-7 . One end of the selector rod  15  is connected to a device that sets the selector rod to spray paint from a desired can, referred to herein as a selector knob  16 . The selector knob may be a projection that turns a switch, a slider, a button or other means of choosing which can of paint is desired. The knob may have a cap-like shape, be an extension of the selector rod itself, or other shape. The other end of the selector rod  15  has a hook  27  that cooperates with an engagement mechanism  20 , as explained in more detail below. The selector rod  15  is rotatable in or alongside the staff, as shown by the curved dashed arrow in  FIGS. 1 and 2 . The selector knob  16  or end of the staff  11  may have indicia to show which can is being selected, as shown in  FIG. 2 . The selector knob  16  is rotated from a first position to a second position, which in turn rotates the hook  27  from a first position to a second position, to select which can of paint will be engaged. See  FIG. 2 . The selector rod rests in a U-shaped guide  18 . The U-shaped guide serves to urge the hook  27  to the center of the guide, thereby encouraging it to be in a neutral position when the trigger is released. This in turn prevents the device from inadvertently continuing to spray paint after the trigger is released, which might happen on occasion if the engagement mechanism  20  or selector rod  15  becomes sticky with dirt or paint and fails to move freely. Optionally the selector rod may be spring biased or use detents to hold it in the selected position. 
     The trigger  14  is connected to the selector rod  15  such that when the trigger is pulled the selector rod moves, preferably in an amount proportional to the depth of the trigger pull. The trigger has a draw stop  32 , which prevents the trigger  14  from being pulled farther than a desired amount, which prevents against inadvertent damage from aggressive use. A trigger spring  28  biases the trigger  14  to default to the off position when not depressed by a user&#39;s finger. See  FIGS. 3 and 5 . 
     The selector rod  15  cooperates with an engagement mechanism  20  such that, when the trigger  14  is pulled, paint sprays from the selected pressurized can. The engagement mechanism  20  comprises a cam  21  and a rocker arm  22 . The cam  21  has two pins extending therefrom, pin  25  relating to can A and pin  26  relating to can B. Rocker arm  22  has two opposing fingers  23  and  24 ; finger  23  to engage can A and finger  24  to engage can B, when selected. The hook  27  of selector rod  15  cooperates with pin  25  or  26  to cause a finger  23  or  24 , respectively, to engage the spray valve (not shown) on the selected can so that paint sprays out. 
     For example, to spray paint from can A, the selector knob  16  is rotated to engage can A. See  FIG. 3 . Then the trigger  14  is pulled, causing the selector rod  15  to be drawn towards the grip  13  and to engage pin  25 . See  FIG. 4 . As a result, the rocker arm  22  is drawn up towards the grip  13 , causing finger  23  to depress the spray valve (not shown) on can A, thus releasing the pressurized paint from can A. 
     Similarly, to spray paint from can B, the selector knob  16  is rotated to engage can B. See  FIG. 5 . Then the trigger  14  is pulled, causing the selector rod to be drawn towards the grip  13  and to engage pin  26 . See  FIG. 6 . As a result, the rocker arm  22  is drawn up towards the grip  13 , causing finger  24  to depress the spray valve (not shown) on can B, thus releasing the pressurized paint from can B. In this manner two different colors of paint, one each from can A and B, can be sprayed using a single device, without the need to change cans of paint. 
     Numerous features serve to ruggedize the device to better support the additional weight of multiple cans and for better resistance to wear, stress, and abuse. Preferably the grip  13  is made of mated halves that fit together to form a pistol-shaped handle. The grip is made of sturdy material such as thermoplastic plastic or aluminum of at least about 0.1 inch and preferably between 0.1 and 0.2 inches thick. The halves are attached together with screws or, in some cases, by snap fit, or both. The halves may be substantially solid, or may be hollow with multiple internal ribs  31   a - g  to strengthen the grip  13 . The draw stop  32  is a rib that prevents the trigger from being drawn back so far that it damages other internal parts. Preferably the selector rod  15  is at least partially encased in the grip  13 , as well as being inside a hollow staff. The engagement mechanism is preferably also housed in the staff to help keep it clean and protected from mechanical harm. The trigger  14  is also preferably encased by the grip  13  except for the portion that the finger touches to pull it, as opposed to a crescent shape that has both curved sides exposed. The trigger  14  is preferably a sliding trigger, as opposed to a pivoting trigger. 
     Optionally one or more flag holders  30  may be attached to the staff  11  for holding marker flags. See  FIG. 8 . Optionally a wheel may be attached at the bottom of the device for rolling the marker stick along the ground. Preferably the wheel is centered between the can holsters  12   a  and  12   b  on a horizontal axis so that the wheel rim extends below the can holster. Alternatively a wheel may be in front or to the side of one can holster, or multiple wheels can be attached, each in front or the side of a can holster. 
     While there has been illustrated and described what is at present considered to be the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made and equivalents may be substituted for elements thereof without departing from the true scope of the invention. Therefore, it is intended that this invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.