Abstract:
20  A grip frame  21  replaces an existing grip frame  1  on a paintball marker in order to convert said paintball marker from a mechanically operated paintball marker into an electro-pneumatic paintball marker. The electronic grip frame  21  utilises an optical sensor in order to detect the operation of a trigger  29  and a second optical sensor to detect the presence of objects within the breech of the paintball marker. Electrical signals from these sensors are taken to an electronic circuit board  24 , which controls the operation of two solenoids (one shown  26 ) in order to fire and recock the paintball marker. A user interface comprising pushbuttons  12, 13, 14  and a multi-character display  16 , allows the user to define how the grip frame  21  functions.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
         [0001]    This application claims the benefit of U.K. Patent Application Ser. No. 0217099.1, filed on Jul. 24, 2002.  
         BACKGROUND OF INVENTION  
         [0002]    This invention relates to a grip frame. The frame is intended to form an integral part of a paintball marker and to be supplied as an upgrade for existing paintball markers.  
           [0003]    A paintball marker, also known as a paintball gun or paintball launcher, is a device used to propel paintballs. A paintball is a spherical object typically 0.68 inch diameter, comprised of a fragile shell which encapsulates a coloured liquid. When a paintball that has been launched from a paintball marker comes into contact with a hard surface, the shell of the paintball ruptures and the coloured liquid is released, leaving a bright mark on the surface.  
           [0004]    One type of paintball marker is a mechanically operated marker. With this type of marker the user pulls a trigger which, through the use of a mechanical linkage, releases a spring-loaded hammer. This hammer is pushed forward by the compressed spring and strikes a spring loaded valve pin, causing the valve to open for a short time and release a burst of compressed gas. This gas burst is internally diverted through the marker such that it passes through a bolt and into the breech of the marker behind a paintball. The expanding gas accelerates the paintball out of the breech, along a barrel and out of the end of that barrel. The continued pull on the trigger actuates a mechanically operated pneumatic valve, which supplies compressed gas to one side of a pneumatic cylinder. This cylinder pushes the hammer back to its starting position and also retracts the bolt to reveal a feed aperture through which a second paintball can drop into the breech. The release of the trigger switches the pneumatic valve back to its original position, supplying compressed gas to the opposite side of the pneumatic cylinder and pushing the bolt back to its original position thus causing the second paintball to be pushed into its firing position, ready for the cycle to start again.  
           [0005]    Another type of paintball marker is an electro-pneumatic marker. This type of marker functions in much the same way as the mechanically operated marker with the exception that the trigger no longer provides the mechanical action required to operate the marker. The trigger in this type of marker operates an electrical switch, which is interpreted by an electrical circuit as the signal to start the firing cycle. This electrical circuit typically employs electro-pneumatic solenoid valves, which drive pneumatic cylinders in order to create the movement necessary to fire and re-cock the marker.  
         SUMMARY OF INVENTION  
         [0006]    The electro-pneumatic paintball marker of the present invention has a much higher rate of fire than a mechanically operated paintball marker and this is a major advantage in modern paintball. The grip frame of the invention is intended for fitting onto a mechanically operated paintball marker in order to convert that marker into an electro-pneumatic marker and thus increase the rate of fire of the marker. The inventive grip frame replaces the entire grip frame of an existing paintball marker along with the hammer release mechanism and the mechanically operated pneumatic valve.  
           [0007]    According to the present invention there is provided a grip frame for a paintball marker or the like comprising a handle, a trigger mechanism associated with the handle comprising a trigger and an electronic sensor associated with the trigger for determining when the trigger has been activated.  
           [0008]    In a preferred embodiment of the invention, the sensor may be optical. Stop means may be provided for limiting the travel of the trigger. The stop means may comprise two adjustable stops limiting travel in opposite directions. Magnetic means may be provided to urge the trigger back to its rest position. Display means may be provided for providing information to the user disposed on that face of the handle facing the user in normal use. These display means may comprise an LED or a liquid crystal display. Advantageously, the display is a multicharacter display. Pushbuttons may be provided in the handle for calibration purposes. The frame may be made of metal or plastics or a combination of both but other materials may also be used. The invention also comprises a paintball marker including a grip frame as defined above. The marker comprises a breech and barrel connected to the grip frame. Advantageously a sensor for sensing the presence of an object in the breech is provided.  
           [0009]    Specifically the breech sensor is used to detect the presence of objects at a position in the breech below the feed aperture through which the paintballs enter the breech. This sensor is used to detect that a paintball is in the breech before the bolt can travel forwards thus preventing the bolt from breaking a ball that has not completely passed through the feed aperture, a major problem when trying to operate other paintball markers at high rates of fire. The sensor is also used to detect that the bolt is fully forwards prior to the marker being fired, thus preventing gas from escaping the breech through the feed aperture and ensuring maximum gas efficiency.  
           [0010]    As the trigger does not operate an electrical switch, as in the case in other paintball markers, but senses the movement of the trigger by means of a sensor, moving parts are reduced which makes the marker more reliable than other paintball markers.  
           [0011]    The use of a magnet and adjustable screw in order to set the amount of force required to actuate the trigger is an improvement over other paintball markers where the trigger operating force can only be varied by replacing a trigger return spring.  
           [0012]    The LED display provides improved viewing in low light conditions over the LCD displays used on other paintball markers. Mounting the display at the rear of the grip frame allows the user to view the display without having to move the paintball marker from its shooting position.  
           [0013]    This is an improvement over the other paintball markers where displays are mounted on either the side of the marker or the side of the grip frame.  
           [0014]    Electrical elements form parts of an electronic circuit which is advantageously battery powered. The battery used to power the electronic circuit makes electrical contact with the related circuit board by means of leaf spring contacts. This is an improvement over other paintball markers which use battery straps on flying leads as these leads often break with use. Longevity for the original marker is increased by providing a means to upgrade rather than replace the marker. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0015]    The novel features which are characteristic of the present invention are set forth in the appended claims. However, the invention&#39;s preferred embodiments, together with further objects and attendant advantages, will be best understood by reference to the following detailed description taken in connection with the accompanying drawings in which:  
         [0016]    [0016]FIG. 1 shows a side elevational view of a prior art mechanically operated paintball marker;  
         [0017]    [0017]FIG. 2 shows a perspective view of an electronic grip frame of the present invention with sear solenoid in place;  
         [0018]    [0018]FIGS. 3 a ,  3   b  and  3   c  respectively show a side elevational view, end elevational view and plan view of the electronic grip frame of FIG. 2 with electronic circuit board and battery in place;  
         [0019]    [0019]FIGS. 4 a  and  4   b  respectively show side and end elevational views of a trigger and trigger sensor forming part of the grip frame of FIG. 2;  
         [0020]    [0020]FIGS. 5 a ,  5   b ,  5   c  and  5   d  respectively show a side elevational view, underplan, plan view and end view of a cocking solenoid and protective manifold forming part of the grip frame of FIG. 2;  
         [0021]    [0021]FIG. 6 diagrammatically shows a hammer release assembly for the grip frame of FIG. 2;  
         [0022]    [0022]FIG. 7 shows a drawing in partial section of a paintball marker in one operative position;  
         [0023]    [0023]FIG. 8 shows a drawing in partial section of a paintball marker in a second operative position;  
         [0024]    [0024]FIG. 9 shows a drawing in partial section of a paintball marker in a third operative position;  
         [0025]    [0025]FIG. 10 shows a functional block circuit diagram for the grip frame of FIG. 2;  
         [0026]    [0026]FIGS. 11 a  and  11   b  show timing diagrams for the paintball marker of FIGS.  7  to  9 ; and  
         [0027]    [0027]FIG. 12 illustrates one possible menu layout for the user interface for the grip frame of FIG. 2. 
     
    
     DETAILED DESCRIPTION  
       [0028]    Referring to FIG. 1, the mechanically operated paintball marker comprises a grip frame  1  firing mechanism comprising body  2  defining a breech  2   a  and barrel  3 . Referring to FIGS. 2, 3 a    3   b  and  3   c , an electronic grip frame  21  to replace the mechanical grip frame  1  is shown. Grip frame  21  comprises a handle  22  defining a cavity  23  in which an electronic circuit board  24  and an electrical battery  25  are located. Above this cavity  23  is a second cavity in which a hammer release assembly comprising a sear solenoid  26 , pin  28  and sear  27  is disposed. This hammer release assembly is controlled by a trigger  29  which is protected by a trigger guard  30  to reduce the possibility of accidental operation. The hammer release assembly will be described in more detail later with reference to FIG.  6 .  
         [0029]    The trigger  29  can be operated by either one or two fingers, the trigger guard  30  being large enough to accommodate two fingered operation. At the rear of the grip frame three recessed holes  9 ,  10  and  11  provide access to three tactile pushbuttons  12 ,  13 ,  14  mounted on the electronic circuit board  24 . This recessing prevents accidental operation of the pushbuttons. Also at the rear of the grip frame, below the pushbutton holes  9 ,  10  and  11  is a transparent window  15  through which can be viewed a multi-character, alphanumeric LED (light emitting diode) display  16 . A slider type switch  17  is located towards the rear of the frame  21  and is used to switch the electrical supply to the electronic circuit board  24 . Channels  18  are cut into the grip frame for the purpose of routing interconnecting cables.  
         [0030]    Referring to FIGS. 4 a  and  4   b , trigger  29  pivots on a pin  19  that passes through the body of the grip frame  21 . The trigger  29  is held onto the pin  19  by means of a set screw  20 . A second set screw  31  locates in a threaded hole through the front of the trigger and acts as a trigger stop. This set screw  31  can be screwed into or out from the hole in order to vary the maximum travel of the trigger  29 . A third set screw  32  locates in a threaded hole through the top of the trigger and also acts as a trigger stop. This set screw  32  can be screwed into or out from the hole in order to vary the rest position of the trigger  29 . A small magnet  35  is located in the grip frame above a fourth set screw  33 . This magnet attracts the set screw  33 , ensuring that the trigger  29  returns to its rest position when released. A prong  34  protrudes from the -rear of the trigger  29  passing through a slot in the grip frame  21 . When the trigger  29  is operated the prong  34  passes through a slotted optical sensor  35 , which is mounted on the electronic circuit board  24  causing the sensor  35  to detect that the trigger  29  has been operated.  
         [0031]    Referring to FIGS. 5 a,    5   b,    5   c  and  5   d,  the cocking solenoid assembly is shown. This comprises an electro-pneumatic solenoid valve  36  mounted onto a protective manifold  37 . The manifold  37  would normally be attached to the front of the paintball marker in place of the existing mechanically operated valve, but it could possibly be mounted elsewhere on the marker. The manifold has pneumatic connections  38  that connect to the existing pneumatics on the paintball marker. The solenoid valve  36  is electrically connected to the electronic circuit board  24  by means of insulated wire  39  and the switching of the valve  36  is controlled by the electronics on the circuit board  24 .  
         [0032]    Referring to FIG. 6 the hammer release assembly is diagrammatically shown. This comprises the sear solenoid  26  which is an electro mechanical solenoid, which is connected to the electronic circuit board  24  and is controlled by the electronics on that board. When the sear solenoid  26  is energised it pushes onto one end of the sear  27  against the action of a sear spring  37  which pivots on pin  28  and releases a spring loaded hammer  40  located in the main body  2  of the paintball marker. When the sear solenoid  26  is de-energised both the sear  27  and the sear solenoid  26  are returned to their rest positions by the sear spring  37 .  
         [0033]    Referring to FIG. 7, a paintball feed tube  42  leads to breech  2   a.  An optical breech sensor  43  is disposed in the breech  2   a.  The firing mechanism comprises a bolt  44  which is shown in its rest position in FIG. 7 and in its cocked position in FIG. 8. In both of these Figures a paintball  45  is shown in the paintball feed tube  42  just above the breech  2   a.  In the position shown in FIG. 7, the bolt  44  prevents movement of the paintball  45  into the breech  2   a.  Cocking the bolt  44  by withdrawing it (to the left in FIG. 7 and  8 ) as shown in FIG. 8 permits the paintball  45  to drop from the paintball feed tube  42  into the breech  2   a  as shown in FIG. 9.  
         [0034]    The electronics on the electronic circuit board  24  comprise a microprocessor  50  which operates to control the functions of the paintball marker under the control of a number of control parameters which are stored in the microprocessor  50  and which may be modified through the pushbuttons  12 ,  13  and  14 . The operation of the paintball marker will now be described with additional reference to FIG. 10 which shows a functional block circuit diagram, FIGS. 7-9 which show the paintball marker in its operative positions and FIGS. 11 a  and  11   b  which show timing diagrams. Each timing diagram shows voltage as the ordinate plotted against time on the abscissa for the trigger sensor  35 , sear solenoid drive  26 , cocking solenoid drive  36  and breech sensor  43 . The diagram of FIG. 11 a  shows the position which obtains when a paintball is present in the breech and the diagram of FIG. 11 b  shows the position when there is no paintball present in the breech. In the former case, the cocking solenoid is deenergised when a paintball is sensed and in the latter case the cocking solenoid is de-energised after a predetermined time if no paintball is sensed.  
         [0035]    [0035]FIG. 7 shows the operative position of the paintball marker prior to the user pulling the trigger  29 . When the user pulls the trigger  29 , the movement of the trigger  29  is detected by the trigger sensor  35  and a digital signal is passed to the microprocessor  50 . The microprocessor  50  then starts the firing cycle by energising the sear solenoid  26  for a short period of time referred to as the sear solenoid on time (SON). This causes the sear  27  to be pivoted and the hammer  40  to be released. The hammer  40  strikes a pin valve and releases a burst of gas, causing the paintball  45  in the breech  2   a  to be propelled from the marker. A short time later after the cocking solenoid on delay (CDEL), the microprocessor  50  energises the cocking solenoid valve  36 , which passes compressed gas to one side of a pneumatic cylinder which pushes the hammer  40  back into its rest position whilst retracting the bolt  44  and opening an aperture that allows a second paintball  45  to fall into the breech  2   a  as shown in FIG. 8. Prior to the fall of the second paintball  45  into the breech  2   a,  the breech sensor  43  detects that the bolt  44  has retracted and that the breech is empty and an analogue signal is passed to the microprocessor  50 . Some time later a paintball passes through the feed aperture and is detected by the breech sensor  43  as shown in FIG. 9.  
         [0036]    The microprocessor  50  de-energises the cocking solenoid valve  36  which returns the bolt  44  to its rest position, closing the aperture and pushing the paintball  45  further into the breech  2   a  as shown in FIG. 7. If no paintball  45  is detected (see FIG. 7) then the microprocessor will deenergise the cocking solenoid valve  36  after a predefined time referred to as the cocking solenoid on time  1  (CON 1 ). The breech sensor  43  detects that the bolt  44  is closed and, a short time later, the firing cycle is completed and can be restarted with another trigger pull.  
         [0037]    As mentioned above, the way in which the marker operates is defined by number of control parameters which are stored within the microprocessor  50 . The user can modify these control parameters by means of the pushbuttons  12 ,  13 ,  14  and the LED display  16 . Each control parameter is accessed through a series of menus and FIG. 10 shows one possible menu layout. This comprises a main menu  60  and a number of subsidiary menus  61 ,  62 ,  63 . To scroll down through the options on each menu, the user presses the lower pushbutton  14 . To scroll up through the options the user presses the upper pushbutton  12 . To select an option the user presses the centre pushbutton  13 . Each subsidiary menu comprise a BACK option. Selecting the BACK option from any menu takes the user back to the previous menu. Once a control parameter is selected then the current value of that control parameter is displayed. Pressing either of the upper or lower pushbuttons at this time takes the user back to the menu from which the control parameter was selected, whereas pressing the centre pushbutton  13  causes the value to flash. When flashing, the parameter can be incremented by pressing the upper pushbutton  12  or decremented by pressing the lower pushbutton  14 . Pressing the centre pushbutton sets the control parameter to the displayed value and the value stops flashing.  
         [0038]    In the exemplary menu of FIG. 12, main menu  60  provides three selectable subsidiary menu options  61 ,  62  and  63  respectively designated Eye Menu, Cycle Menu and Display Menu. The Eye menu  61  provides three selectable options in addition to the back option which enable the bolt detection level, empty breech detection level and ball detection level to be calibrated. Detection is optical and optical characteristics can vary from paintball marker to paintball marker causing variation in generated signal levels. Calibration takes account of these variations.  
         [0039]    The Cycle menu  62  provides five selectable options in addition to the back option. They are the sear solenoid on time, cocking solenoid on delay, cocking solenoid on time  1 , which have already been referred to earlier in the description of the operation of the sear and cocking solenoids  26  and  36 , and cocking solenoid on time  2  and sear solenoid on delay which relate to an operating mode where the breech sensor is switched off. The Display menu  63  enables the brightness level of the display  16  to be altered to suit personal requirements.  
         [0040]    It will be appreciated that the above embodiment has been described by way of example only and that many variations are possible without departing from the scope of the invention. For example, the paintball marker may be operated in other modes than those described.