Abstract:
A detent body with a center bore is secured to the chamber wall of a paint-ball gun. A floating detent with a hollow core and a domed tip reciprocates within the center bore, allowing the tip to extend into the chamber to restrict movement of a paint ball. Axially aligned slots extend through opposing sides of the floating detent. A pin extends through the slots and corresponding pin holes in opposing sides of the detent body to create a stationary abutment for limiting axial movement of the floating detent. A compressive spring disposed within the hollow core between the pin and the inner end urges the outer tip into the chamber. A set screw threaded into the end of the hollow core engages the pin and the floating detent. Rotation of the set screw regulates axial movement of the outer tip into and out of the chamber.

Description:
This application claims priority from provisional application No. 60/484,110 filed Jun. 30, 2003. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to paint ball sport guns. More particularly, the invention relates to an adjustable ball detent assembly for constraining a paint-ball in the gun chamber prior to firing. 
   2. Description of the Related Art 
   Paint-ball sport guns are typically provided with a ball-detent mechanism for retaining a paint-ball in the gun chamber prior to firing. Such mechanisms commonly include a sphere resting on a helical spring, or a detent member comprising a body with a hemispherical section on its tip. The mechanism is secured to the side of the gun chamber, so that a ball-detent protrudes into the chamber and blocks the path of the ball from the chamber to the barrel. Because of the snug fit between the chamber/gun-barrel and the paint-ball, protrusion of a ball-detent, even a small distance into the chamber, will block the ball from rolling into the barrel prior to actuation, such as occurs when the sport gun is fired. 
   Because the ball-detent protrudes into the chamber most commonly by the force of a spring, if pressure is applied to the ball-detent, the spring will compress. As the spring retracts, the ball-detent collapses into the detent body, thereby allowing the paint-ball to move past the ball-detent and into the gun barrel. After the paint-ball passes the ball-detent, the spring returns the ball-detent to its extended position, again protruding into the chamber and retaining the next paint-ball within the chamber. 
   The distance the detent-ball must travel to retract flush with the inner surface of the chamber, affects the speed at which successive paint-ball rounds can be fired. Additionally, the mechanical process of retraction into the detent body and returning to an extended position can be felt by the gun operator. This mechanical/sensory feedback affects the shooters sense of smoothness and rhythm for discharging a paint ball. Experienced shooters develop individual preferences for the feel of this action. 
   The diameter and uniform roundness of paint balls is also known to exhibit slight variations between manufacturers, or even separately produced paint-ball batches by a single manufacturer. The thickness of the shell, pressure of paint inside the shell, and even the age of the paint ball can further affect the deformation of the paint ball as it passes the detent mechanism. As a result, the smoothness of operation, rhythm of the bolt action, and resistance offered by the ball-detent and the “feel” to the operator can vary from paint ball batch to paint ball batch. 
   Because ball-detent assemblies are typically mounted by rotation it into a threaded detent-hole, to individualize the feel of the action, paint-ball shooters sometimes unscrew the assembly a select amount to affect the distance the ball-detent extends into the chamber. However, once the ball-detent assembly is loosened, it is free to rotate, and tends to unscrew. As a result, the ball-detent gradually protrudes less and less into the chamber. At first, this affects the “feel” of the gun. As the unscrewing continues, the paint-ball can roll from the chamber to the barrel prematurely. Eventually, the loosened ball-detent can unscrew completely, falling out of the gun, and often being lost somewhere in the playing field. 
   There is, therefore, a need for a method and apparatus for individualizing the mechanical feedback of a shooting cycle for a particular shooter. There is further a need for a ball detent that extends into a chamber a distance consistent with the preferences of an individual shooter without loosening the engagement of the ball-detent assembly in the detent-hole. Additionally, there is a need for a detent mechanism that can be easily and reliably adjusted according to the particular parameters and variations of each batch of paint balls. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention is directed to a method and apparatus for individualizing the mechanical feedback of a shooting cycle for a particular shooter. The present invention is also directed to a ball detent that extends into a chamber a distance consistent with the preferences of an individual shooter without loosening the engagement of the ball-detent assembly in the detent-hole. Additionally, the invention provides an adjustment means to accommodate particular variations in the definable parameters of a batch of paint balls, including but not limited to diameter, uniform roundness, hardness of the shell, thickness of the shell, and pressure of the paint within the shell. 
   A paint-ball sport gun includes a chamber in communication with a source of paint balls. The chamber is coupled to a barrel. An advance mechanism is configured to forcibly advance a paint ball from the chamber into the barrel during actuation. As used herein, a detent-assembly comprises a detent body and a floating-detent with an outer tip. 
   The floating-detent is configured to reciprocate between a first position and second position. In the first position, the outer tip of the floating detent protrudes a first distance into the chamber that is sufficient to block passage of a paint ball into the gun barrel. In the second position, the outer tip does not protrude into the chamber, thereby allowing passage of the paint ball. 
   A securing means fixes the detent-assembly to the gun. The securing means comprises a threaded detent-hole extending through a side wall of the chamber. The detent-assembly has a body with a threaded nose configured to engage corresponding threads in the detent-hole. The first distance that the outer tip protrudes into the chamber is adjustable through an adjustment means separate from the securing means. 
   The detent assembly includes a resilient member, preferably a compression spring, configured to urge the floating detent toward the first position. The floating detent has a substantially cylindrical shape with a first end comprising a dome shaped outer tip. The floating detent has a hollow core with an open end and an opposing closed end defined by an inner surface. The open end provides the entrance to the hollow core. The resilient member is disposed within the hollow core. The inner surface of the open end includes a detent threaded portion. The adjustment means comprises a threaded set screw threadably engaged with the above detent threaded portion. 
   The floating detent may have a curved or polygonal cross-section. Preferably, it is cylindrical and symmetrical about a center axis. The floating detent has a first slot and a second slot extending through corresponding opposite detent side walls. The slots have a length that is aligned parallel to the center axis. A cross pin is oriented about perpendicular to the center axis and extends across the hollow core and through each of the first and second slots. The resilient member is disposed within the hollow core and extends from the cross pin to the interior closed end. 
   The body of the detent assembly has a first pin opening and a second pin opening that extend through corresponding opposing body walls. Opposite end portions of the pin are held within respective first and second body pin openings. A pin O-ring extends around the periphery of the body and overlies the first and second pin holes to prevent the cross pin from falling out. A nose O-ring extends around a nose portion of the body and functions to frictionally secure the detent assembly to the external surfaces of the gun chamber. 
   A method for adjusting the distance that the floating-detent outer tip protrudes into the chamber of the paint ball gun comprises the steps of rotating the set screw, which is threadably engaged with the floating detent, axially moving the floating detent in a direction corresponding to the direction of rotation of the set screw; and decompressing or compressing the spring disposed within the hollow core of the detent cylinder in accordance with the direction of the rotation of the set screw. The set screw is adjusted without the necessity of loosening the threaded engagement between the body of the detent assembly and the gun, as is common in the prior art. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a left side isometric view of a paint-ball sport gun having a cut-out area showing the paint-ball loading chamber of the gun in communication with the detent assembly of the present invention. 
       FIG. 2  is a right side elevational view of the paint-ball sport gun shown in  FIG. 1 . 
       FIG. 3  is a cross sectional view taken along lines  3 — 3  of  FIG. 2 . 
       FIG. 4  is a front isometric exploded view of the detent assembly shown in  FIG. 3 . 
       FIG. 5  is a enlarged top plan view of the detent assembly shown in  FIG. 3 . 
       FIG. 6  is a cross sectional view taken along lines  6 — 6  of  FIG. 5 . 
       FIG. 7  is a front isometric view of the detent assembly shown in  FIG. 5 . 
       FIG. 8  is an enlarged fragmentary view taken along lines  8 — 8  of  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1 and 2  are different views of a paint-ball sport gun  10  illustrating various operational features of the overall gun. A magazine feed  11 , in the form of a hollow cylindrical member with a funnel portion at the lower end, feeds a paint ball  12  into the loading chamber  13 . The paint-ball  12  comprises a spherical breakable shell containing a dye or paint. Upon impact in competitive shooting, the spherical shell breaks open and deposits paint onto a target. The spherical shell is typically a deformable plastic that is rigid enough to substantially maintain its spherical shape in flight. The ball, however, deforms and flattens as it impacts the target. This functionality is important since paint balls are fired at people in competition. Therefore, they are engineered to inflict minimal pain, discomfort or injury to a person impacted by the paint-ball  12 . 
   To actuate the discharge of the paint-ball  12 , a user pulls a gun trigger  14 . Bolt  15  of the gun then slides forward along the gun axis c,c, pushing the ball into the gun barrel  19 . The bolt  15  is typically a hollow cylindrical member with an outer diameter slightly smaller than the diameter of the paint ball  12 . The end of the bolt  15  that contacts the paint-ball  12  is concave with a radius of curvature that corresponds to the shape of the paint-ball outer shell. This matching configuration facilitates maximum contact area between the bolt  15  and the paint-ball  12 , more evenly distributing the force of the bolt against the paint-ball as the bolt  15  advances. After the ball  12  is fed from the magazine feed  11  into the chamber  13 , it must remain in the chamber  13  until actuation. 
   Once the paint-ball  12  is in the gun barrel  19 , compressed air or carbon dioxide accelerates the paint-ball out the end of the barrel toward a target. To facilitate a minimum of air leakage, the inner diameter “d” of the barrel  19  is about identical to the outer diameter of the paint-ball  12 . 
   A floating detent  16  reciprocates within a detent body  21 . The detent body is threadably secured within a detent hole  18  formed through the side wall  17  of the chamber  13 . When the outer tip  23  of the floating detent  16  projects into the chamber  13 , it prevents the paint-ball from inadvertently rolling out of the chamber  13  and into the barrel  19 . 
   As best illustrated in  FIG. 8 , the floating detent tip  16  is urged into the chamber  13  by a resilient member, such as helical compression spring  29 . The outer tip  23  of the floating detent is dome-shaped and provides a rounded outer surface. Therefore, when the bolt  15  forcibly advances the paint-ball  12 , the paint-ball slides across the domed surface, dividing the force imparted to the paint ball into a linear aspect in line with the direction of travel of the bolt  15 , and a perpendicular aspect in line with the direction of travel of the floating detent  16 . This action thereby causes the floating detent to retract and permit passage of the paint ball into barrel  19 . 
   According to a preferred configuration, the rounded surface of outer tip  23  comprises a smooth, rigid hemispherical segment. However, other curved or angular inclined shapes are envisioned within the scope of the present invention. 
   According to the preferred embodiment, when the floating detent  16  is pushed backward by the paint ball, the direction of travel of the floating detent is not more than about ninety degrees from the direction of travel of the bolt. Although angles more than ninety degrees are envisioned within the scope of the present invention, excessive force and friction may be required to depress the floating detent, which could cause the paint-ball to rupture. Accordingly, such excessive angles are not preferred. For tooling purposes, it is usually easiest to drill a hole through the side wall  17  of chamber  13  at right angles to the direction of travel of the bolt  15 . 
   The detent-assembly  20  includes a detent body  21  threadably secured to the wall  17  of the chamber through a threaded detent hole  18  in the chamber wall  17 . A center bore  33  extends coaxially through detent body  21  along longitudinal axis a,a. The center bore has a diameter d 2 , which is slightly greater than the outside diameter of the detent part  24 . Therefore, the floating detent  16  can be inserted into the center bore  33  and freely reciprocate therein as described above. 
   The detent body  21  further includes a first pin opening  34  and a second pin opening  35  for a purpose to be hereinafter described. The pin openings preferably have identical shapes and extend through opposing walls of the detent body. 
   The outer tip  23  of floating detent  16 , when in an unextended state, projects into the chamber  13  by a distance d 1 . When the floating detent  16  is depressed by the paint-ball  12 , the outer tip  23  will be substantially flush with the interior wall  22  of the chamber  13 . 
   As discussed above, the detent assembly is adjustable such that the distance d 1 , which the outer tip  23  of the floating detent  16  protrudes into the chamber  13 , can be adjusted to the desired “feel” of an individual shooter. This assembly can further be re-adjusted at any time to compensate for variations in the various parameters of a paint ball that can affect the smoothness of operation, rhythm, speed or feel of the chambering of a paint ball during actuation. 
   As best seen in  FIGS. 4–8 , the floating detent  16  comprises a detent part  24  with an outer tip  23  at an outer end portion. The detent part may have a curved or polygonal cross-section. In the preferred embodiment shown, it has a cylindrical shape and the outer tip comprises a spherical section. 
   The opposing inner end portion of the detent part  24  has an open end portion  27  extending into a hollow core  46 , which terminates at closed end portion  47 . The inner surfaces of the open end portion  27  are provided with inner threads  26  for engaging corresponding set screw threads  43  as described below. An elongated first slot  25  extends through a first wall portion of the detent part  24 , and an elongated second slot  28  (shown in phantom) extends through an opposing second wall portion of the detent part. The slots are preferably located proximate open end portion  27 , and are directly opposite each other. They have about identical shapes, and are oriented parallel to the center axis a,a ( FIG. 4 ) of the detent assembly  20 . 
   The first and second slots  25 ,  28  have a width that is sufficient to allow a cross pin  45  to extend through both slots. As the floating detent  16  reciprocates, it is guided both by the center bore  33  of the detent body  21 , and by the cross pin  45  extending through the slots. The floating detent  16  can reciprocate back and forth in center bore  33  with the maximum axial movement defined by the length of the first and second slots. 
   The pin  45  is preferably a solid shaft having a length sufficient to span hollow core  46  and extend into the aforementioned first pin opening  34  and second pin opening  35 . Preferably, the pin openings are located within a first groove  36  of the detent body  21 , within which is fitted a pin O-ring  39 . The pin length will correspond to the diameter of the first groove. In this way, when the floating detent  16  is slidably engaged within center bore  33  of the detent body, opposing ends of the cross pin  45  will transit through opposing walls of both the detent part  24  and the detent body  21 . Subsequent placement of the pin O-ring in first groove  36  will constrain the pin in its operative position. 
   Within detent part hollow core  46 , is a resilient member shown as compression spring  29 . The spring has an outer diameter that is less than the hollow core  46  diameter so that the spring  29  can fit into the core. The spring should have sufficient length to be slightly compressed between pin  45  and closed end  47 . In this way, the floating detent will always be biased toward an outermost first position. Examples of alternative resilient members are elastic plugs, flex strips, pneumatic mechanisms, piston assemblies and washer springs. 
   The detent body  21  comprises an outer body portion  50  that extends to a threaded nose portion  30 . The body may be formed from a solid material, such as metal, plastic or a curable cast resin that may be molded or tooled. The nose portion  30  includes exterior nose threads  31  that threadably engage the corresponding chamber wall threads  48  within detent hole  18 . A shoulder  32  is formed at the juncture of the outer body portion  50  and the nose portion  30 . 
   Although optional, the outer body portion  50  is shown with a second groove  37 . The second groove is located adjacent the first groove  36  to provide a receptacle for a spare O-ring  40 . 
   A nose O-ring  38  is sized to compress against the shoulder  32  while disposed snugly around the periphery of the nose  30 . This O-ring functions to inhibit loosening of the detent body from its threaded engagement with detent hole  18 . The nose O-ring also provides a sealing engagement with the outer chamber wall  17  that surrounds detent hole  18 . The pin and spare O-rings  39 ,  40  are identically sized to respectively fit securely within either one of the first groove  36  and second groove  37 . 
   As best shown in  FIG. 4 , a set screw  41  is provided having set screw threads  43  configured to engage inner threads  26  in the open end portion  22  of detent part  24 . Inner face  42  of the set screw abuts against pin  45 . The outer end  44  of the set screw has a tool engagement means, known in the art, for engaging a tool. The engagement means may comprise a blade slot, projection, Phillips recess or socket opening which is shaped to accommodate a tool such as an Allen wrench, socket wrench or screwdriver. 
   With the above arrangement, it can be seen that rotation of the set screw with a tool while inner end  42  is abutted against pin  45 , will translate the screw pitch into axial movement of the floating detent  16 . The extent of axial movement per revolution of the set screw will be dictated by the pitch of the inner threads  26  of the detent cylinder and corresponding set screw threads  43 . The set screw  41  will preferably be a selflocking set screw, having a locking part such as an elastic collar, plastic insert or a locking nut member known in the art. 
   Assembly 
   Referring primarily to  FIG. 4 , compression spring  29  is inserted into the hollow core  46  of the detent part  24  through the open end portion  27 . The detent part is then moved into the center bore  33  of the of the detent body  21  such that the outer tip  23  of the floating detent  16  is oriented toward nose  30 . The detent part may now be rotated so that the first and second slots  25 ,  28  are aligned with respective first and second pin openings  34 ,  35 . 
   After achieving the above orientation, pin  45  is moved through the aligned pin openings and slots. During movement of the pin  45  through the hollow core  46  of the detent part  24 , spring  29  must be pressed “forward” (toward the outer tip  23 ) with a narrow tool such as a nail or screw driver, so that the pin can pass freely behind the spring. When assembly has been completed properly to this point, the spring  29  will be compressed between the pin and the inner end of hollow core  46 . 
   The pin O-ring is now placed around the first groove  36  to prevent the pin from becoming dislodged from the slots and pin openings. The optional spare O-ring  40  may be secured in the second groove  37 . In this way, the spare O-ring will be conveniently available to replace the pin O-ring. 
   The nose O-ring is slipped over nose  30  and around shoulder  32 . The detent body  21  is then gripped by the fingers, and the nose threads  31  are rotatably engaged with corresponding chamber wall opening threads  48 . Rotation of the detent assembly into opening  18  is continued until the outer surface of the gun chamber wall  17  compresses the nose O-ring  38  and sealingly secures the detent assembly  20  to the gun. The set screw  41  is then rotated into engagement with inner threads  26  of the detent part  24  until inner face  42  engages the transversely extending pin  45 . 
   Operation 
   Because pin  45  is mounted in first and second pin openings  34 ,  35  in the detent body  21  of the assembly, and the detent body  21  is threadably secured to the gun chamber wall  17 , the pin  45  cannot move relative to the gun  10 . More specifically, when the inner face  42  of set screw  41  is rotated against the pin  45 , it cannot push the pin forward. Consequently, the force is translated to an axial motion, wherein the inner threads  26  of the floating detent will move the floating detent forward or backward, depending on the direction of rotation. Consequently, the distance d 1  that the outer tip  23  extends into the chamber  13 , can be conveniently increased or decreased. A user can visually observe the distance which the outer tip  23  is protruding into the chamber  13  while simultaneously rotating the set screw  41 . Rotation can continue until the desired protrusion distance d 1  is achieved. 
   One method used by shooters to adjust the protrusion distance d 1  is to visually observe the relationship of the detent to a paint-ball in the chamber. Variations in paint-ball diameter or roundness of paint balls may be visually apparent to some shooters. Alternatively, or in conjunction with visual adjustment, a user can discharge a paint-ball round and note the feel of the advance mechanism during chambering. According to the feel of the discharge of the round, the user will determine if the distance d 1  that the outer tip  23  protrudes into the chamber  13  should be increased, decreased, or remain as it is. The user can continue to re-adjust the set screw  45  and re-fire the gun until the feel is according to the user&#39;s preference. 
   A particular advantage of the claimed invention relates to the fact that the adjustment of the set screw takes place while the detent assembly  20  is secured to the gun chamber. Accordingly, the detent assembly  20  does not have to be loosened from the gun  10  to adjust the depth d 1 . 
   Those skilled in the art will also recognize that the compressed nose O-ring  38  acts like a lock washer by maintaining a linear force on the threads, and thereby reduces the ability of the detent assembly  20  to unscrew. In a similar manner, spring  29  has a selected length and compression strength to maintain a continual outward pressure from the pin  45  to the outer tip  23  to maintain an outward bias on the outer tip. However, the outward bias should not exceed the rupture point of the paint-ball shell. 
   Within the foregoing description, many specific details commonly understood by those skilled in the art have not been recited so as to not needlessly obscure many of the essential features of the present invention. In other instances, some non-essential details of the present invention have been recited in the detailed description to better enable the reader to make and use the claimed invention. The many details within the foregoing description are, therefore, not intended to limit the scope of the claims appended hereto, said claims being intended to cover alternative structures, processes, modifications, and equivalents which may be included within the spirit and scope of the foregoing description and the appended claims.