Abstract:
The invention discloses two related improvements over existing trigger mechanisms utilized in pneumatic launching devices—such as pellet or paintball guns. The first improvement is a method for allowing a single trigger frame configuration to be utilized by a multiplicity of launching devices despite differences in attachment points and/or mechanical linkages inherent in the same. The second improvement relates to incorporating a trigger return mechanism within the trigger frame which utilizes magnets, pneumatics or mechanical means to actively return the trigger to its initiating or ‘rest’ position after it has been operated.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This present application is a Continuation-in-Part of application Ser. No. 09/990,504, filed on Nov. 21, 2001 now U.S. Pat. No. 6,802,305, which claims priority to Provisional Application Ser. No. 60/252,230, filed on Nov. 21, 2000. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention generally relates to the pneumatic launching devices typically used in the sport of paintball and related applications. More specifically, the present invention relates to a trigger frame housing which can be utilized by a wide variety of different launching devices, and to the incorporation of an active return trigger mechanism built into the frame. 
     As the game and sport of paintball has grown and become more popular, a variety of manufacturers, each producing its own models of paintball marker have entered the industry. Additionally, those same manufacturers, as well as others, provide numerous aftermarket accessories for use with their products; there are in fact, numerous manufacturers who&#39;s sole business is the design and manufacture of aftermarket components for different paintball marker lines, the components adding features and capabilities desired by consumers. 
     Typically, most paintball markers are built and sold as ‘standard’ models, such models incorporating basic features. A good example of this are the original manufacturers&#39; barrels supplied with the markers. These are usually simple tubes of a diameter capable of handling a wide range of paintball sizes and are generally built as inexpensively as possible. Most consumers will typically purchase an aftermarket barrel shortly after the purchase of the marker and will select from among as many as a hundred different designs of barrel in choosing the features they most desire. 
     As the sport has evolved, aftermarket features other than barrels have also become desired by consumers, including the ‘grip frame’—the portion of the marker which is held by the user&#39;s hand and which incorporates the trigger. Numerous styles have evolved and different features, such as finger grooves for comfort, built-in game timers, multiple finger triggers and approximately sized trigger guards, as well as others, have been developed for the market. 
     Finally, an increasing reliance on volume fire has evolved. This reliance on an increase in volume fire is evidenced by the introduction of electronically enhanced guns, improved paintball magazines and paintball feeding mechanisms, improved high speed valves and regulators and a host of other technologies all having a common goal of increasing the rate of fire from the paintball gun. 
     The goal of increasing the rate at which paintballs can be fired is complicated by an industry prohibition on “fully automatic” firing mechanisms, multiple shot weapons or other enhancements which allow the user to fire more than one paintball per trigger cycle of the weapon. Therefore, an objective throughout the paintball industry is to enhance the rate of fire through various means which maintain the operation of the paintball gun in a true “semi-automatic” firing mode in which one projectile is expelled per complete cycle of the trigger/gun mechanism. Further, a desire exists to eliminate, assist or equalize the force exerted by the use throughout the trigger cycle and to provide a powered or assisted method of returning the trigger to the ready position at the end of the firing sequence. 
     Despite previously mentioned solutions and enhancements, there are currently no methods available for an “assisted” trigger mechanism in a paintball gun. In principle, an assisted trigger mechanism utilizes the user&#39;s own mechanical action of pulling or releasing a trigger mechanism as the initiating force, after which mechanical, pneumatic, electronic, magnetic or a combination of these means is introduced and automatically perform some or all of the trigger cycle. 
     Because of the numerous styles and designs of paintball marker on the market today, it would be desirable to be able to provide a single grip frame assembly which would incorporate features desired by consumers and which could be utilized by numerous marker designs; distributors and retailers would be able to reduce their inventory requirements and consumers would be able to migrate such a frame—with advanced features—from one market to another, rather than having to purchase an entirely new grip frame with every marker. 
     In order to understand the scope of the present invention, it is necessary to understand that there are currently four “classes” of paintball gun design, each of which has a different configuration but all of which operate on the same principles of design. 
     The first of the four mechanisms of paintball gun operation is classified as a blowback configuration. This type of gun utilizes a mechanically operated sear connected to the trigger, a spring operated hammer connected mechanically to a bolt, and a spring operated valve mechanism. The bolt is located above the hammer in a separate body channel which is in communication with the gun barrel. In operation, the user first “cocks” the system by pulling a cocking knob connected to the bolt. This causes the hammer to be moved behind the sear and compresses the hammer spring. 
     When the trigger is pulled, the trigger actuates a sear, releasing the hammer. Under spring tension, the hammer moves forward. Since the bolt is connected to the hammer, when the hammer moves forward, the bolt moves forward as well to push a paintball into the barrel. When the bolt is at its furthest point of forward travel, a gas passage in the bolt is in communication with a vent hole from the valve. Simultaneously, the hammer impacts a valve stem in the face of the valve, opening the valve and releasing a preset amount of pressurized gas. This gas vents through the bolt, thus firing a paintball, and against the hammer, pushing the hammer and the bolt back into the cocked position. At its rearmost point of travel, the sear once again captures the hammer completing the cycle. 
     The next type of paintball gun uses a “blow forward” type of mechanism in which the bolt is retained by the sear, which is mechanically linked to the trigger. The bolt rides on a tube that communicates with the valve and is retained by the sear under pressure, effectively acting as a seal on the valve system. When the trigger is actuated, the bolt is released. Gas pressure from the valve pushes the bolt forward, which in turn pushes a paintball into the barrel. Once the bolt has reached its furthest point of travel, the gas passage is opened, allowing the gas to flow through the face of the bolt, thus firing the paintball. A spring located forward of the bolt returns the bolt where it is again captured by the sear, thus completing the cycle. 
     An “autococking” style of semi-automatic paintball guns operate in the same basic manner as the blowback semi-automatic. However, the design is based on what was originally a pump operated paintball gun where the pumping action has been pneumatically automated. This style of design therefore has several additional mechanisms. 
     In the autococking style mechanism, when the trigger is pulled, the hammer is released, striking the valve and sending gas through the bolt and down the barrel, thus firing a paintball. Gas is also vented to a low pressure regulator, which in turn supplies a three-way valve. The three-way valve is connected to a pneumatic ram, which in turn is mechanically linked to a cocking mechanism and to the bolt. 
     Gas from the regulator is introduced into the three-way valve which first operates the ram to push the cocking mechanism rearward, pulling the bolt back, allowing a new projectile to enter the barrel and resetting the hammer on the sear. Gas is then vented from the three-way valve, which operates to reverse the flow of gas to the ram, which in turn pulls the bolt and cocking mechanism forward, completing the cycle. 
     The final type of paintball gun is classified as an electric paintball gun. In some cases, electric paintball guns replaced some or all of the mechanical systems mentioned above with electronic or electromechanical systems. For example, one widely distributed model substitutes an electronic switch connected to a solenoid for the mechanical sear. 
     In each of the types of paintball guns discussed above, the firing rate of paintballs is limited by the rate at which a human finger can depress and release the trigger of the paintball gun. Since the rate at which a human finger can pull a trigger is somewhat limited by the mechanical action of the trigger mechanism, it is an object of the present invention to provide assistance to the user when pulling the trigger and actively assist in returning the trigger to its initial position. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a grip frame and trigger housing for use with paintball markers which is configured for attachment to a wide range of paintball marker bodies and which incorporates an active return mechanism. The grip frame is manufactured so that different trigger and sear mechanisms can be fitted and will work operationally with different marker bodies. Additionally, the grip frame incorporates one of several different mechanisms which actively return the trigger/sear assembly to the ‘ready-to-fire’ position without being activated by the user. 
     In the first embodiment of the invention, the grip frame upper body is sized to mate with the largest (in all dimensions) marker body and contains a number of passages cut through the grip frame body which align with the mounting passages of the different marker bodies. 
     Because all paintball marker bodies are made to accommodate the same sized projectile, the differences in length and width of the different model bodies do not prohibit the use of a single sized grip frame body for attachment to all of them. 
     Sear pin mounting holes and trigger pin mounting holes are cut through the body at a height and location which matches the requisite positioning for each of the markers the grip frame will be attached to and perpendicular to the main axis of the grip frame. A slot is cut into the interior of the grip frame body, the slot sized to accommodate the largest trigger and sear assembly required to operate one of the markers the grip frame will be attached to. 
     In one embodiment of the invention, a secondary magnet or electromagnet is positioned behind the trigger in the trigger housing. The secondary magnet in the trigger housing is used to attract the trigger during initial movement of the trigger rearward, while the polarity of the secondary magnet can be reversed to repel the trigger once the paintball has been fired. 
     In another embodiment of the invention, the trigger itself is configured as part of an electromagnet. User actuation of the trigger causes the circuit between the trigger/electromagnet and a power supply to be closed. The magnetic field thus created causes the trigger to be attracted to a secondary magnet behind the trigger while being simultaneously repelled by a secondary magnet positioned in front of the trigger. Once the trigger has traveled past the point where it actuates the sear mechanism of the paintball gun, the circuit to the trigger electromagnetic is opened, causing a cessation of the magnetic field. Once the trigger has traveled a minute but discernable distance beyond that required to cause a firing event, the circuit is again closed such that the polarity of the trigger electromagnet is reversed. At this point in the trigger cycle, the magnetic field repels the trigger from the secondary magnet positioned behind the trigger, while the secondary magnet in front of the trigger acts to attract the trigger. 
     In another alternate embodiment, an adjustment mechanism consisting of a non-ferrous “field strength reducer” is positioned between the secondary magnet in the trigger housing and the trigger. The field strength reducer, when placed between the secondary magnet and the trigger, reduces the strength of the magnetic field emanating from the secondary magnet. The type and size of the field strength reducer can be selected to vary the amount of assistance provided by the secondary magnet. 
     In a further embodiment of the invention, the magnets can be replace by a single or a pair of solenoids that are mechanically linked to the trigger. Movement of the trigger during the firing sequence causes activation of the solenoids which extend their solenoid rods to aid in movement of the trigger during the firing sequence. 
     In another embodiment of the invention, Hall effect sensors are attached to the electromagnets positioned in the trigger housing. As the trigger is depressed, the change in the field strength monitored by the sensors will alternately cause either power to be transmitted to the electromagnet, the polarity of the magnet change, or power will be cut off to the electromagnet. In this way, the user&#39;s actuation of the trigger, and the positioning of the trigger, can be monitored and adjusted. 
     In addition to aiding in the actuation of the trigger itself, an alternate embodiment of the invention contemplates replacing the mechanical linkage between the trigger and the cocking/firing mechanism with a pneumatic operating system. In this embodiment of the invention, rearward movement of the trigger opens a pneumatic air valve. As the pneumatic air valve is opened, air pressure is supplied to an actuating ram coupled to the cocking ram of the paintball gun. When the actuating ram is pressurized, the air pressure of the actuating ram operates the cocking/firing mechanism to cause a paintball to be fired. In this manner, the air pressure of the actuating ram causes the mechanical movement of the cocking/firing mechanism, rather than a mechanical linkage between the trigger and the cocking/firing mechanism. The use of air pressure rather than the mechanical linkage allows for a faster and less physically demanding movement by the user on the trigger. After the firing sequence has been initiated, the residual pressure within the pneumatic valve aids in returning the trigger to its pre-firing position. 
     In another embodiment of the device, an adapter plate or plates is used, the adapter plate having channels which mate with the mounting channels of a marker body and which has additional mounting channels for mating with the grip frame body. In yet another embodiment of the device, the adapter plate incorporates sear pin and trigger pin mounting holes cut through the body perpendicular to the long axis of the mounting plate. In another embodiment of the device, the adapter plate incorporates magnets, which are operable on the trigger, such that the trigger is repelled by the magnets when pulled and attracted by the magnets when released. 
     In another embodiment of the device, a pneumatic ram is activated by operation of the trigger and, upon completion of the firing sequence, the ram operates against the trigger to return it to its initiating position. 
     Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  illustrates a side view of a current art trigger frame 
         FIG. 2  is a side view of one embodiment of the universal grip frame illustrating multiple mounting channels 
         FIG. 3  is a side view of an embodiment of the universal grip frame illustrating the adapter plate 
         FIG. 4  is a side view illustrating the location of a pivoting trigger mounted in the grip frame 
         FIG. 5  is a side view illustrating the locating of a sliding trigger and sear assembly mounted in the grip frame 
         FIG. 6  is a side view illustrating the various non-contiguous locations of trigger mounting pins and sear mounting pins for different styles of trigger assemblies 
         FIG. 7  is a top view illustrating two different styles of current art sear and trigger slots milled into a grip frame and the slot in the universal grip frame capable of accommodating both 
         FIG. 8  is a side view illustrating the location of active return mechanism magnets mounted in the grip frame 
         FIG. 9  is a side view illustrating the first embodiment of the assisted trigger mechanism of the present invention; 
         FIG. 10  is a second embodiment of the assisted trigger mechanism of the present invention, illustrating a force limiting element between the actuator and triggers 
         FIG. 11  is side view of the third embodiment of the assisted trigger mechanism of the present invention; 
         FIG. 12  is a fourth embodiment of the assisted trigger mechanism of the present invention; 
         FIG. 13  is a side view of the fifth embodiment of the assisted trigger mechanism of the present invention; 
         FIG. 14  is a side view of the sixth embodiment of the assisted trigger mechanism of the present invention; 
         FIG. 15  is a side view illustrating an autococking mechanism constructed in accordance with the present invention; and 
         FIG. 16  is a second embodiment of the autococking mechanism incorporating the features of the present invention. 
         FIG. 17  is an alternate embodiment of a grip frame according to the present invention. 
         FIG. 18  is an overhead view of a grip frame according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring first to  FIG. 1 , thereshown is a generally schematic illustration of the trigger portion of a paintball gun. The paintball gun includes a handle portion  10  that is grasped by a user during use of the paintball gun. The handle  10  is connected to a trigger mechanism  12  that includes a trigger guard  14  and the actual trigger  16 . The trigger  16  is coupled to the cocking and firing components of the paintball gun such that depression of the trigger  16  will cause a paintball to be discharged from the paintball gun. The trigger mechanism  12  of the present invention is a conventional mechanism used in currently available paintball guns. 
     The present invention may provide a secondary magnet  18  is positioned within the trigger housing behind the actual trigger  16 . In the preferred embodiment of the Invention, the secondary magnet  18  could be either a natural magnet or an electromagnet that can be energized by an external circuit (not shown). As illustrated in  FIG. 1 , the trigger  16  also includes a trigger-mounted primary magnet having a known polarity. 
     In the embodiment in which the magnet  18  is a natural magnet, the magnet is oriented such that its polarity is aligned in the direction of trigger travel. The polarity of the secondary magnet  18  is arranged such that the polarity of the secondary magnet  18  and the polarity of the trigger mounted magnet are opposite such that as the trigger  16  moves toward the magnet  18 , the magnet  18  repels the trigger to provide an assisted return for the trigger  16 . The strength and position of the secondary magnet  18  are selected such that the secondary magnet  18  repels the trigger  16  only after the trigger  16  has been depressed far enough to actuate the sear. After the sear has been actuated, the secondary magnet aids in returning the trigger to the resting position. 
     In an alternate embodiment in which the secondary magnet  18  is an electromagnet, the polarity of the secondary magnet  18  and the polarity of the trigger mounted magnet are opposite such that the trigger is initially attracted toward the secondary magnet  18 . Once the trigger  16  activates the sear for the paintball gun, a sensor detects such movement and the polarity of the secondary magnet  18  is reversed, such that the secondary magnet  18  repels the trigger  16  to aid in returning the trigger  16  to its resting position prior to actuation of the next firing sequence. 
     Referring now to  FIG. 2 , thereshown is an alternate configuration of the embodiment shown in  FIG. 1 . As illustrated in  FIG. 2 , the trigger  16  includes a trigger magnet  20  and a secondary magnet  22  is positioned within the trigger housing. In the embodiment of the illustrated in  FIG. 2 , a shim  24  is positioned between the secondary magnet  22  and the trigger magnet  20 . The shim  24  is formed from a material that, when placed in front of the secondary magnet  22 , reduces the strength of the magnetic field emanating from the secondary magnet  22 . Thus, each individual shim  24  reduces the magnetic field by a predetermined amount. In this manner, the attraction force between the secondary magnet  22  and the trigger magnet  20  can be adjusted such that the secondary magnet  22  repels the trigger only after the sear of the paintball gun has been activated. Thus, the shim  24  helps control the amount of assistance provided by the trigger mechanism of the present invention. 
     Referring now to  FIG. 3 , thereshown is another alternate embodiment of the assisted trigger mechanism. In the embodiment illustrated in  FIG. 3 , the trigger  16  is configured as part of either an electromagnet or a natural magnet. The mechanism includes a secondary magnet  26  positioned in front of the trigger  16  and a secondary magnet  28  positioned behind the trigger  16 . As the trigger  16  is activated, the trigger  16  causes a circuit between the trigger  16  and a power supply to be closed. The power supply causes the magnetic field created by the secondary magnet  26  to repel the trigger  16 , while the magnetic field created by the secondary magnet  28  positioned behind the trigger  16  attracts the trigger. Once the trigger  16  has traveled past the point where it actuates the sear mechanism, the circuit to the electromagnets is open, causing a cessation of the magnetic field. Once the trigger  16  has traveled a minute but discernable distance beyond that required to cause the firing event, the circuit is again closed, such that the polarity of the magnetic fields of the secondary magnet  26  and the secondary magnet  28  are reversed. At this point in the trigger cycle, the magnetic fields repel the trigger from the secondary magnet  28  behind the trigger, while the secondary magnet  26  in front of the trigger attracts the trigger  16 . 
     As shown in  FIGS. 1-3 , an adjustment mechanism can be utilized for each of the secondary magnets that allows the magnet to be moved closer or farther away from the trigger and the trigger-mounted primary magnet in one embodiment, the secondary magnet can be mounted on a screw that can be threaded into the body of the mechanism housing the trigger, such that the depth or height of the screw can be adjusted externally. In another embodiment, the adjustment mechanism consists of a holder, into which secondary magnets of differing strengths can be placed. 
     In yet another embodiment, the adjustment mechanism consists of a secondary magnet that has been machined to include external threads on the outer circumference of the magnet and a tool socket is formed on the outward face of the magnet, such as a slot or hex-head. In this embodiment, the magnet is placed into a threaded channel machined into the trigger mechanism which houses the return mechanism. In another alternate embodiment, the threaded channel can be cut into the center of the magnet, allowing it to be placed on the adjustment screw. By providing such adjustment mechanisms, the strength of each secondary magnet can be adjusted to vary the amount of attraction and repulsion forces created during the trigger cycle. 
     Referring now to  FIG. 4 , thereshown is yet another alternate embodiment of the assisted trigger mechanism. In the embodiment illustrated in  FIG. 4 , a pair of solenoids  30  and  32  are connected to the trigger  16 . The solenoid  30  includes a solenoid rod  34  while the solenoid  32  includes its own solenoid rod  36 . As the trigger  16  is depressed, the trigger  16  trips a sensor which supplies power to the solenoid  30 . When actuated, the solenoid  30  extends the solenoid rod  34  to aid in movement of the trigger  16  to the firing position, 
     As the trigger  16  continues its rearward movement, the trigger further trips a sensor indicating that the trigger  16  has activated the sear mechanism. After actuating the sear mechanism, power is supplied to the solenoid  32 , which extends the solenoid rod  36 . Extension of the solenoid rod  36  aids in returning the trigger  16  to its resting position prior to initiation of the firing sequence. 
     Referring now to  FIG. 6 , thereshown is another embodiment in which a pair of sensors  38  and  40  are positioned on opposite sides of the trigger  16 . The sensors  38  and  40  detect the movement of the trigger between its operating positions. The sensors  38  and  40  are coupled to a circuit-board  42  mounted in the handle of the paintball gun. The circuit board  42  includes various logic elements, electronic connections between the circuit and sensors and switches, electronic connections to pneumatic, electronic, magnetic or other types of actuating devices, and interconnected power supplies. The electronic circuit contained on the circuit board  42 , through communications with the sensors  38  and  40 , can track, analyze and respond to the operation of the trigger by the user and will assist both the actuation and return of the trigger as desired. 
     Referring now to  FIG. 5 , Hall effect sensors  44  and  46  are positioned relative to the trigger  16  such that as the trigger  16  moves toward one of the sensors  44  and  46 , the change in field strength monitored by the sensors will alternately cause power to be transmitted to the electromagnets, such as shown in  FIG. 3 . Movement of the trigger  16  will thus cause the polarity of the electromagnets to change or will cut off the flow of power to the electromagnets  26  and  28 . In this way, the user&#39;s actuation of the trigger  16 , and the positioning of the trigger can be monitored and adjusted. 
     Although not shown in the drawings, in another alternate embodiment could provide a pneumatic on/off valve positioned behind the trigger such that when the trigger is depressed far enough to actuate the sear of the paintball gun, the pneumatic on/off valve is opened. When the pneumatic on/off valve is opened, a ram is pressurized. As the ram is pressurized, an actuation rod extends to aid in moving the trigger back to its resting position. 
     In the embodiment described in  FIGS. 1-6 , the active trigger mechanism is used to aid in the depression and return of the trigger between its two operating positions. The mechanisms allow for the trigger to be depressed and released at a higher rate of speed to aid in increasing the number of paintballs that can be fired by the operator. However, in each embodiment, the active trigger mechanism is used to move the trigger itself, while the trigger is part of a cocking/firing mechanism used to operate the sear of the paintball gun. 
     Referring now to  FIGS. 7 and 8 , thereshown is an alternate configuration that is utilized as an autococking mechanism, rather than simply a trigger return. In the embodiments illustrated in  FIGS. 1-6 , the trigger is mechanically coupled to the sear of the paintball gun such that the mechanical linkage between the trigger and the sear is used to both cock and fire the paintball gun. In the embodiment of the invention illustrated in  FIGS. 7 and 8 , the mechanical linkage between the trigger  16  and the sear Is removed and a cocking ram  48  having an actuating rod  50  is coupled to the sear to effectuate the cocking and firing of the paintball gun. Thus, since the trigger  16  is no longer mechanically coupled to the sear, the trigger  16  can be depressed and released with less effort by the user. 
     As illustrated in  FIG. 7 , a rod  52  is coupled to the back side of the trigger  16  and extends through the trigger housing  54 . The far end of the rod  56  is in contact with a movable plunger  58  of a pneumatic on/off valve  60 . The pneumatic on/off valve  60  is contained in the handle  10  of the paintball gun. The on/off valve  60  includes an air inlet  62  that receives a supply of regulated air pressure from an external source  64 , such as the air supply used to operate and fire paintballs from the paintball gun. An outlet  66  from the on/off valve  60  supplies air pressure to an actuating ram  68  as illustrated. The actuating ram  68  receives the opposite end of the actuating rod  50 . 
     During operation of the paintball gun, the user depresses the trigger  16  to move the trigger  16  rearward to fire a paintball. As the trigger  16  moves rearward, the rod  52  depresses plunger  58  which opens the on/off valve  60 . When the on/off valve  60  is opened, the actuating ram  68  is pressurized through the air inlet  67 . After being pressurized, the actuating ram  68  moves the actuating rod  50 , which initiates the firing/cocking sequence for the paintball gun. As can be understood by the above description, the movement of the trigger pressurizes the actuating ram such that the actuating ram cocks and fires the paintball gun instead of a mechanical linkage between the trigger and the cocking/firing mechanism of the paintball gun. 
     Once the paintball has been fired, the trigger  16  is released, which closes the on/off valve  60 . As the trigger is released, the residual pressure within the on/off valve  60  aids in pushing the plunger  58  and thus the rod  52  forward, acting as an active return for the trigger  16 . Once the firing sequence is complete, the on/off valve  60  is vented and the system awaits the next firing sequence. 
     Turning now to  FIG. 8 , thereshown is an alternate embodiment, with like parts having corresponding reference numerals. As illustrated in  FIG. 8 , the actuating ram  68  and the cocking ram  48  are connected in parallel with each other, unlike the opposed configuration illustrated in  FIG. 7 . The actuating ram  50  is received in both the cocking ram  48  and the actuating ram  68  and is coupled to the sear (not shown) of the paintball gun. As illustrated, the air outlet  66  from the on/off valve  60  is again received at an air inlet  67  for the actuating ram  68 . 
     During operation of the invention illustrated in  FIG. 8 , the user initially pulls back the trigger  16 , which again opens the on/off valve  60  by depressing the plunger  58 . When opened, the on/off valve  60  supplies a source of pressurized air to the actuating ram  68  through the air inlet  67 . Once pressurized, the actuating ram  68  moves the actuating rod  50  of the cocking ram  48  to begin the cocking sequence. Once the paintball has been fired, the trigger  16  is released and the residual pressure within the on/off valve  60  causes the plunger  58  to aid in the return of the trigger  16  to its previous position. Once again, the actuating ram  68  is vented to atmosphere such that the system is ready for the next firing sequence. 
     The present invention provides for a universal trigger frame including an active trigger return mechanism for use with a pellet and paintball applications. In short, the present invention, the first set of embodiments of  FIGS. 9 through 16  illustrate a method and configuration to aid in moving the trigger between its two positions during the firing cycle. In these embodiments, the trigger is mechanically linked to the cocking and firing mechanism of the paintball gun such that the mechanism aids in reducing the amount of force required by the user to complete the firing sequence. By reducing the amount of force required, the speed of the firing sequence can be increased such that the number of paintballs fired by the user during a given time period can be increased. 
     In the second type of system, as illustrated in  FIGS. 7 and 8 , a mechanical linkage between the trigger and the cocking/firing mechanism for the paintball gun is eliminated and a pressurized actuating ram is used. In this system, the trigger closes an air valve, which begins the firing sequence. Once again, since the user does not need to actuate the mechanical linkage between the trigger and the cocking/firing mechanism, the rate at which the trigger can be pulled and released is increased, thus increasing the number of paintballs that can be fired during a given time period. In each of the two embodiments illustrated, assistance is given to the user during the trigger cycle such that the speed of the trigger cycle can be increased, effectively increasing the number of paintballs fired by a semi-automatic paintball gun. 
     Referring now to  FIGS. 9 through 16 ,  FIG. 9  displays a typical paintball marker grip frame such as may be used with any of the above-mentioned embodiments incorporating the mounting surface  111  for attachment to a marker body, the trigger housing  112  and the grip  110 .  FIG. 10  shows the location of mounting channels for one typical model of marker body  120 , and mounting channels for another typical marker body  121 . 
       FIG. 11  shows the universal grip frame  110 , standard mounting channels through the mounting surface of the grip frame  125 , and adapter plate  130  sized to fit between the grip frame  110  and the marker body  128 , attachment points  126  for attaching the grip frame  110  to the adapter plate  130  and mounting channels  127  in the adapter plate  130 , aligning with mounting channels  129  in the marker body  128 , with the mounting channels  127  in the adapter plate  130 . In use, screws would first be used to attach the adapter plate  130  to the marker body  128  mounting channels  129  and then the grip frame  110  would be attached to the adapter plate  130 , using the mounting channels  126 . 
       FIG. 12  shows a grip frame  110 , incorporating a pivoting trigger  131 , mounted on the grip frame using a pivot pin  132  mounted through the grip frame body.  FIG. 13 , shows a grip frame  110 , a sliding trigger  133 , a guide pin  137  mounted perpendicularly to the main axis of the grip frame, a sear pin  136 , mounted perpendicularly to the main axis of the grip frame, a sear  135  mounted on the sear pin  136  and a trigger access hole  134 , cut into the body of the grip frame. Referring now to  FIG. 14 , thereshown a grip frame  110 , a pivoting trigger  138 , a pivoting trigger mounting pin  139 , a sliding trigger  140 , a trigger access hole  141 , a sear pin  142  and a sear  143 . 
     These three figures serve to illustrate that a single grip frame  10 , can accommodate the mounting holes required for incorporating a variety of different trigger and sear mechanisms within a single grip frame. Referring now to  FIG. 15  thereshown the mounting channels  152  &amp;  153  in the upper surface of the grip frame for one style of marker  150 A and the interior cavity  151  in the grip frame required to house the trigger, in  150 B the interior channel  154  in the grip frame required to house the trigger of a different style marker and in  150 C the interior channel  155  that can accommodate both styles of trigger and sear assembly in both style markers. 
     Referring now to  FIG. 16  which shows a grip frame  110 , a pivoting trigger  162 , a magnet mounted on the rear surface of the trigger  163 , an adjustable magnet housing mounted on the inside of grip frame  164 , a magnet mounted in the housing  165 , a magnet mounting channel through the main body of the grip frame  160  and a return magnet  161  mounted in the channel. 
     In operation, the magnet  163  mounted in the trigger  162  is arranged so that its outer surface polarity is the same as the magnet  165  mounted in the magnet housing  164 , such that the two magnets will repel each other. The magnet housing  164  can be adjusted in order to increase or decrease the relative strength of the magnetic field(s) of the trigger magnet  163  and body magnet  165 , allowing the user to adjust the amount of return force on the trigger after it has been pulled.