Patent Publication Number: US-6658982-B2

Title: Cocking knob and striker arrangement for gas-powered projectile firing device

Description:
BACKGROUND 
     This invention relates to gas-powered projectile firing devices, such as paintball markers, and in particular, to a cocking knob and striker arrangement for such devices. 
     Paintball markers typically are powered by a compressed gas, such as CO 2 , which is released in a burst in the chamber behind a paintball to propel the paintball out of the barrel of the marker. The barrel is attached to a receiver that houses a bolt slidable in the chamber, a valve for controlling gas flow, and a spring-loaded striker that slides below the bolt. A trigger and sear assembly holds the striker in a rear, cocked position, and releases the striker when the trigger is pulled so that it moves forwardly under spring pressure to open the valve momentarily, releasing a metered quantity of gas into the chamber. 
     The striker and the bolt are linked together by a connecting pin so that they move in unison, the bolt serving to advance one paintball at a time from the breach, where paintballs are loaded through a ball feed port, into the chamber and seal the chamber from the feed port. A cocking handle or knob attached to the striker allows the user to pull the striker rearwardly to the cocked position, ready for firing. Most paintball markers are semi-automatic, i.e., gas pressure re-cocks the marker with each firing, so that manual cocking is required only when the gas supply is connected, and for the initial shot. 
     In prior art markers the cocking handle has a threaded end that screws into the striker, the other end of the handle projecting from the side of the marker and having a screwdriver slot for turning the cocking handle. The coil spring that drives the striker rests against the rear end of the striker, in some cases in a recess or a blind hole. When disassembling the marker for cleaning, there are many threaded connections that must be undone, the connection between the cocking handle and the striker being one such connection. Simplification of the disassembly and reassembly process is a desirable objective. 
     SUMMARY OF THE INVENTION 
     The invention accomplishes the aforementioned and other objectives by providing an improved cocking knob for moving the spring-loaded striker of a gas-powered projectile firing device rearwardly into a cocked position ready for firing. The cocking knob comprises an elongated member having a longitudinal axis, a proximal portion adapted for operative connection with the striker and a manually engageable distal portion, the proximal portion having a rearwardly facing spring seat adapted to engage the striker spring. 
     The spring seat preferably comprises a recess adapted to receive the front end of the striker spring. The spring seat recess may comprise a pair of spaced notches in which the front end of the striker spring can rest. 
     The proximal portion of the cocking knob preferably has a striker seat adapted to operatively engage the striker, the engagement of the striker spring and the spring seat serving to prevent disengagement of the striker seat from the striker. Conversely, disengagement of the striker spring from the spring seat affords easy disengagement of the cocking knob from the striker, without having to unscrew the cocking knob. The striker seat may comprise a generally J-shaped recess which opens generally axially and forwardly, the spring seat being disposed on the rear side of the longer leg of the J. 
     According to a second aspect, the invention provides a gas-powered projectile firing device comprising a receiver, a striker slidable in the receiver, a striker spring biasing the striker forwardly, and a cocking knob comprising an elongated member having a longitudinal axis, a proximal portion adapted for operative connection with the striker and a manually engageable distal portion, the proximal portion having a rearwardly facing spring seat adapted to engage the striker spring. 
     The proximal end of the cocking knob may have a J-shaped recess as described above that engages a substantially upright pin attached to the striker. The striker may have an axial bore at the rear end thereof and a lateral opening ahead of the rear end which opens into the axial bore, so that the proximal portion of the cocking knob extends through the lateral opening into the axial bore, and the striker spring extends forwardly into the axial bore to engage the spring seat on the proximal portion of the cocking knob. 
     According to a third aspect, the invention provides a gas-powered projectile firing device comprising a receiver; a chamber in the receiver; a bolt slidable in the chamber; a barrel at the front end of the receiver aligned with the chamber; a striker slidable in the receiver parallel to and below the chamber; a connecting pin interconnecting the striker and the bolt so that they move in unison; a valve assembly in the receiver forwardly of the striker; a striker spring in the receiver biasing the striker forwardly toward the valve assembly; a sear and trigger assembly for controlling the motion of the striker; and a cocking knob for moving the striker rearwardly into a cocked position ready for firing. The cocking knob comprises an elongated member having a longitudinal axis, a proximal portion engaging the connecting pin and a manually engageable distal portion, the proximal portion having a rearwardly facing spring seat which engages the forward end of the striker spring. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     An embodiment that incorporates the best mode for carrying out the invention is described in detail below, purely by way of example, with reference to the accompanying drawing figures, in which: 
     FIG. 1 is a side elevational view of a paintball marker incorporating the novel cocking knob and striker arrangement according to the invention; 
     FIG. 2 is a longitudinal sectional view of the marker of FIG. 1; 
     FIG. 3 is an exploded view of the marker of FIG. 1; 
     FIG. 4 is a perspective view of the cocking knob according to the invention as seen from the bottom and the rear; 
     FIG. 5 is a top plan view of the cocking knob of FIG. 4; 
     FIG. 6 is a front elevational view of the cocking knob of FIG. 4; 
     FIG. 7 is a proximal end view of the cocking knob of FIG. 4; and 
     FIG. 8 is a top plan view of the cocking knob, partly in section, showing its engagement with the connecting pin and the striker spring. 
    
    
     It is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components of the preferred embodiment described below or illustrated in the drawing figures. 
     DETAILED DESCRIPTION 
     FIGS. 1-3 depict a paintball marker embodying the features of the invention with the moving parts shown in the uncocked position. The marker comprises a receiver  10 ; a barrel  12  threaded into the receiver ahead of a chamber  13 ; a grip assembly  14 , with a trigger  16  and a sear  17 , attached to the receiver by means of screws  18 ; a ball inlet  20  through which paintballs are fed (e.g., from a hopper); and an internally threaded adapter  22  for connection to a source of compressed CO 2  which is fed to the receiver through hose  24 . A safety  26  cooperates with the trigger mechanism in a known manner to lock or unlock the trigger. A resilient ball stop  27 , beneath cover  27   a , keeps the paintball in chamber  13  from sliding out of barrel  12  before firing. 
     A valve plug  28  and valve set screw  28   a  retain a valve assembly  29  in receiver  10 . To the rear of valve assembly  29  is a striker  30  which is urged forwardly by a striker spring  34  that extends into striker  30  through a rear bore  31 . A cocking knob  36  operatively engages striker  30  through a lateral opening  32 , and projects outwardly from the receiver through a slot  19 . A striker plug  38  retains striker  30 , striker spring  34 , a spring guide  37 , a spacer  37   a  and a bumper  39  in receiver  10 . A velocity adjustment screw  38   a  is carried by striker plug  38 . A bolt plug  40  seals off the back end of receiver  10  behind the bolt  42 . Various O-rings  44  act as seals between mating parts, where needed. 
     A connecting pin  50  links together striker  30  and bolt  42  so that they move in unison. Specifically, connecting pin  50  extends through a vertical bore  43  in bolt  42 , through an open vertical space  11  in receiver  10 , and into a vertical bore  33  in striker  30 . Thus, in a manner known in the art, forward movement of striker  30  upon firing will advance bolt  42  to move a paintball forwardly in chamber  13 , whereupon it is propelled through barrel  12  by a burst of CO 2  fed through the bolt when the striker actuates valve assembly  29 . Gas pressure then returns striker  30  to its cocked position, held to the rear against the force of striker spring  34  by sear  17 . This brings bolt  42  back to its initial position, allowing the next paintball to fall through ball inlet  20  into firing position in chamber  13 . 
     Connecting pin  50  is removable for disassembly through a hole  15  in the top of receiver  10 . The connecting pin has a threaded bore  52  at its top end which allows a similarly threaded tool to engage and extract the connecting pin. For example, spring guide  37  may serve as such a tool when provided with a male thread at its forward end that mates with the female thread in connecting pin  50 . A circumferential groove  54  near the bottom of connecting pin  50  cooperates with the proximal portion of cocking knob  36  as described below. 
     Referring to FIGS. 4-8, cocking knob  36  is a generally elongated member having a proximal portion  56  adapted to engage connecting pin  50 , and an ergonomically configured distal portion  58  adapted for comfortable hand engagement when pulled rearwardly to cock the marker. Proximal portion  56  has a J-shaped recess  60 , the curved portion of which closely fits into groove  54  in connecting pin  50  (see FIG.  8 ). Cocking knob  36  thus retains connecting pin  50  in striker  30  and bolt  42 . 
     J-shaped recess  60  opens generally axially (i.e., lengthwise of the cocking knob) and forwardly (i.e., toward the front of the marker). The shorter leg  61  of the J extends sufficiently around connecting pin  50  to provide a shoulder which positively forces the connecting pin rearwardly (in the direction of arrow R in FIG. 8) when the cocking knob is pulled rearwardly to cock the marker. The longer leg  62  of the J lies to the rear of J-shaped recess  60  and has on its rear face a spring seat comprising a pair of spaced notches  64  forming a recess in which the forward end of striker spring  34  rests. Forward spring pressure against cocking knob  36  prevents disengagement of the cocking knob from connecting pin  50  because the striker spring  34  cooperates with the shoulders of notches  64  to prevent axial movement of the cocking knob (i.e., laterally of the marker). 
     During disassembly of the marker, in particular disassembly of the striker and the cocking knob, striker plug  38  is first removed to gain access to striker spring  34 . Bumper  39 , spring guide  37 , spacer  37   a  and ultimately striker spring  34  are removed. With striker spring  34  disengaged from the spring seat (notches)  64 , cocking knob  36  is easily pulled laterally out of receiver  10  and out of engagement with connecting pin  50 . Disassembly of other parts of the marker, e.g. connecting pin  50 , bolt  42 , etc., can then be carried out in the conventional manner. Reassembly involves reversal of these steps. In either case, the lack of a threaded connection between cocking knob  36  and connecting pin  50  makes for a simpler, easier and faster procedure. 
     While a J-shaped recess  60  in cocking knob  36  is preferred, a recess of any suitable configuration may be used as long as it affords the required working engagement between the cocking knob and the connecting pin described above. For example, a generally V-shaped recess would appear to satisfy these criteria, and would allow for the advantageous simple disengagement and reengagement described above. 
     Further, while the seat for striker spring  34  preferably is formed by two spaced notches  64 , any type of spring seat may be provided on the rear of cocking knob  36  as long as it adequately seats striker spring  34  and provides sufficient resistance to lateral withdrawal of cocking knob  36  when the striker spring is engaged therewith. For example, a simple flat-bottomed recess on the rear of the cocking knob would appear adequately to seat striker spring  34  and prevent withdrawal of cocking knob  36 . 
     Still further, while the proximal portion of cocking knob  36  is disclosed as cooperating with a separate connecting pin  50 , it is to be understood that the inventive concept disclosed herein is applicable to an arrangement wherein the cocking knob engages another element associated with the striker, whether it be integrally formed with the striker or separately formed and assembled therewith. 
     Various other modifications will be apparent to those skilled in the art without departing from the scope of the invention, which is defined by the appended claims.