Abstract:
A hydraulic buffer assembly for use in a paint gun includes a sealed housing having first and second ends and an interior including a chamber containing a hydraulic fluid. A piston assembly including at least one piston rod and a piston head is axially movable through the interior of the housing, wherein the piston head includes at least one orifice through which hydraulic fluid flows when the piston assembly is moved under load. The buffer assembly is configured to decrease or slow the firing rate of an automatic paint gun.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority under relevant portions of 35 U.S.C. §119 and 37 CFR §1.53 to U.S. Patent Application No. 62/330,455, entitled: Hydraulic Buffer Assembly, filed May 2, 2016, the entire contents of which are incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    This application is generally directed to the field of buffer assemblies and more specifically to a hydraulic buffer assembly that is preferably configured for use in an automatic or semi-automatic paint ball gun or marker. The hydraulic buffer assembly produces a time delay or lag in order to effectively control the firing rate of the paint ball gun. 
       BACKGROUND 
       [0003]    Paint ball guns or markers are commonly used for recreational purposes as well as for police and military training. Typically, a paint ball gun launches a projectile under force, typically using an expanding gas such as compressed air or carbon dioxide, at a muzzle velocity of approximately 90 m/sec (about 300 ft/sec). Upon impact with a target of interest, the projectile (paint ball) releases a stored quantity of brightly colored paint. Greater velocities can be achieved, but have been regulated due to safety concerns. Over time, these devices have become fairly sophisticated and complex, wherein semi-automatic and automatic versions have been developed, and in which the firing or burst rate has also seen significant increases. For example, some paint guns are capable of firing up to thirty (30) rounds per second. 
         [0004]    Specific regulations in various states in the United States, as well as different foreign countries dictate that the firing rate of automatic paint ball guns or markers must be controlled within specific maximums, in the interest of safety. Accordingly, there is a need in the field to provide a buffer assembly that can be incorporated into new or existing paint guns or markers in order to slow the firing rate of an automatic paint gun within the promulgated standards. Though electronic versions having complex circuitry have been developed, to date, Applicant is unaware of a hydraulic buffer being configured for incorporation or inclusion within a paint ball gun. 
       BRIEF DESCRIPTION 
       [0005]    According to a first aspect, there is provided a buffer assembly for creating a time delay upon receipt of an inputted load or force while maximizing the receipt of a return force. The apparatus includes a housing having a first end and a second end with a piston assembly extending within an interior of the housing. The piston assembly includes an orificed piston head that moves a contained hydraulic fluid based on the stroke of the piston upon receipt of an applied load, the movement of hydraulic fluid creating a time delay to the inputted load or force. The piston assembly also includes a check valve for fast return of the piston assembly in the opposite direction so that the buffer assembly is ready to provide a time delay for the next firing cycle. In at least one version, the above assembly can be used within a paint ball gun and more specifically, an automatic paint ball gun for purposes of controlling firing rate. 
         [0006]    According to one version, the piston assembly includes a first piston rod and a second piston rod secured together axially, as well as a glide ring and a seal retainer, each disposed between the piston head and an interior wall of the housing. 
         [0007]    In at least one embodiment, the glide ring and seal retainer include through openings aligned with one another and the orifices of the piston head that permit the passage of hydraulic fluid when the piston assembly is moved through the interior of the housing under load. 
         [0008]    The first piston rod can include a narrowed end portion that is secured within an opening of the second piston rod and in which the second piston rod is secured to the seal retainer, the seal retainer being configured for movement with the piston assembly. 
         [0009]    The glide ring is preferably disposed between the piston head and the seal retainer and is disposed for movement based on movement of the piston assembly. According to one version, the buffer assembly includes a pair of quad rings that are fixedly secured within the interior of the housing within spaced regions, each of the spaced regions being smaller than the quad rings and therefor compressing same. 
         [0010]    In at least one version, the orifices of the piston head include at least one check valve and in which the seal retainer has an outer diameter that is smaller than an inner diameter of the housing, thereby creating an annular space for moving hydraulic fluid. 
         [0011]    The piston head can be defined with an outer diameter that is smaller than an inner diameter of the housing, thereby creating an annular space for moving hydraulic fluid in addition to the orifices, when the at least one check valve is open. 
         [0012]    The glide ring can be defined by an outer diameter that almost matches the inner diameter of the housing to act as a seal on the inner diameter of the housing, the glide ring including an opening to permit the passage of hydraulic fluid for buffering purposes. 
         [0013]    According to another aspect, there is provided a method for slowing the firing rate of an automatic paint gun, the method comprising:
       providing a housing secured within the paint gun having first and second ends and an interior including a chamber containing a hydraulic fluid;   providing a piston assembly including a pair of piston rods and a piston head that is axially movable through the interior of the housing, the piston head including at least one orifice; and   applying a load attributable to firing the paint ball gun to a first piston rod, causing hydraulic fluid to be moved through the orifices of the piston head and damping the assembly by controlling the velocity of the buffer when being stroked in one direction during the firing and return cycle of the gun, causing a time delay and thus slowing the firing rate.       
 
         [0017]    In one version, the piston assembly includes the pair of piston rods that are attached to one another at opposing ends, in which the pair of piston rods are configured to move in tandem. A piston head attached to one of the piston rods includes a set of orifices through which hydraulic fluid moves when the piston head is advanced. 
         [0018]    One advantage realized by the herein described design is that the firing rate of an automatic firearm, such as a paint ball gun, can be more effectively and mechanically controlled, as opposed to electronic means as conventionally employed, the latter being less reliable, more complex and expensive and also requiring electric power. 
         [0019]    Another advantage of the herein described design is that the buffer assembly is sufficiently compact to fit within a very small area of the gun. As a result, the overall footprint of the gun is not compromised or effected. 
         [0020]    These and other features and advantages will be readily apparent from the following Detailed Description, which should be read in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    Various features and advantages of the present invention will become more apparent when taken in conjunction with the following description and drawings wherein identical reference numerals have been used, where possible, to designate identical features that are common to the figures, and wherein: 
           [0022]      FIG. 1  is a side elevational view of a hydraulic buffer assembly in accordance with an embodiment; 
           [0023]      FIG. 2  is the side elevational view, taken in section, of the hydraulic buffer assembly of  FIG. 1  in a first or expanded position; 
           [0024]      FIG. 3  is the side elevational view of  FIG. 2  of the hydraulic buffer assembly in a second or compressed position; 
           [0025]      FIG. 4  depicts a buffer assembly shown schematically in connection with a paint gun; and 
           [0026]      FIG. 5  is a side elevational view of a paint gun that is configured for use with a buffer assembly in accordance with an embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    The following discussion describes a hydraulic buffer assembly or apparatus that is made in accordance with a specific embodiment. It will be understood, however, that various modifications and variations can be made within the ambits of the herein described concept. In addition, certain terms such as “first”, “second”, “inner”, “outer”, “above”, “below”, “left”, right”, “interior”, “exterior”, and the like are used throughout the course of discussion in order to provide an suitable frame of reference with regard to the accompanying drawings. It should be noted, however, that these terms, unless specifically indicated otherwise, are also not intended to narrow the scope of the invention. In addition, similar parts described in the various views are labeled with the same reference numbers for the sake of clarity and understanding. 
         [0028]    With reference to  FIG. 1 , there is depicted a hydraulic buffer assembly  100  defined by a substantially cylindrical assembly housing  104  having respective first and second ends  108 ,  112  and a center axis  110 . A clevis or similar connecting member  116  is attached relative to the first end  108  of the housing  104 . According to this described embodiment, the clevis  116  includes a center hole or opening  120 . 
         [0029]    Referring to  FIGS. 1 and 2 , the housing  104  is defined by an interior  105  wherein the clevis  116  is fixedly attached to a piston assembly and more specifically an extending end of a first piston rod  124 . A set screw  129  is fitted within respective end openings of the clevis  116  and the first piston rod  124 , wherein the end of the clevis  116  includes an annular shoulder  117  that engages the end of the first piston rod  124  to reliably position or seat same. 
         [0030]    The interior  105  of the assembly housing  104  is substantially hollow and is sized and configured to retain a plurality of components of the herein described hydraulic buffer assembly  100 . A retainer  128  is disposed in the interior  105  of the assembly housing  104  at the first end  108 . The retainer  128  includes a center opening  130  that is sized and configured to receive the first piston rod  124  and in which an outer wall of the retainer  128  is pressed flush with an interior or inner wall  107  of the assembly housing  104 . Adjacent the retainer  128  and contained within the housing interior  105  is a front bearing assembly  135  that is sealingly and fixedly engaged with the inner wall  107  of the assembly housing  104 . 
         [0031]    According to this embodiment, the bearing assembly  135  includes an annular recess  137  that is sized and configured to retain a sealing ring  138 , the latter preferably being elastomeric in nature which is disposed within the recess  137  and in sealing contact with the inner wall  107  of the assembly housing  104 . The bearing assembly  135  further includes a center opening  139  that is sized and configured to permit the passage of the first piston rod  124  and in which the bearing assembly  135  otherwise essentially fills the interior space of the assembly housing  104  at the first end  108 , with the exception of a recessed portion  141  adjacent the retainer  128  that receives a quad ring  145 . 
         [0032]    As shown in the sectioned view according to  FIGS. 2 and 3 , the recessed portion  141 , the outer wall of the first piston rod  124 , and an interior wall of the retainer  128  combine to define a spaced region that fully encloses the quad ring  145 . According to this embodiment, the size of this latter defined spaced region is preferably smaller than the quad ring  145  in order to create an interference fit and induce compression. 
         [0033]    The piston assembly further includes a piston head  150  that is secured to a shoulder of the first piston rod  124 , the latter being axially movable along with the first piston rod  124  and attached fixedly thereto. According to this embodiment, the piston head  150  is defined by a cylindrical body including an outer diameter that is smaller than that of the inner surface  107  of the housing  104 , thereby forming an annular gap. The piston head  150  further includes a center opening  154  that receives a narrowed diametrical portion  158  of the first piston rod  124  that further passes thorough an opening  164  formed in an adjacent glide ring  162 . An expanded portion of the piston head  150  retained against the shoulder of the first piston rod  124  includes a set of axially disposed orifices  153 . According to this embodiment, the orifices  153  are radially disposed beyond the first piston rod  124  such that the orifices  153  extend through the entirety of the expanded portion. A narrowed portion of the first piston head  124  extends axially from the expanded portion, the latter having a smaller outer diameter. 
         [0034]    Still referring to  FIGS. 2 and 3  and according to this embodiment, the glide ring  162  has an outer diameter that almost matches the inner diameter of the assembly housing  104  and in which the narrowed diametrical portion  158  of the first piston rod  124  further extends through the formed center opening  172  of a seal retainer  170  adjacent the glide ring  162 . The seal retainer  170  receives the smaller diametrical portion  158  of the first piston rod  124 , the latter passing through the formed center opening  172 . In addition and according to this embodiment, the seal retainer  170  includes a recessed portion  174  on a facing surface closest to the second end  112  of the housing  104  that is sized to receive the end of a separately attached second piston rod  190 , as well as an annular passage  176 . 
         [0035]    According to this embodiment, the second end  112  of the assembly housing  104  includes a spacer  180  that is press fitted to the inner surface  107  of the assembly housing  104 . The spacer  180  is fixedly attached to the assembly housing  104  and is defined by a center opening  184  through which extends the second piston rod  190 , the latter being part of the piston assembly and having an end opening  194  that is sized to accommodate the end of the narrowed diametrical portion  158  of the first piston rod  124 . The piston rod  190  which is also axially movable extends through an opening  109  formed in the interior wall  107  of the housing  104  and extends into a chamber  200  filled with a hydraulic fluid, such as a silicone fluid. 
         [0036]    A quad ring  210  is disposed within a fixed spaced region  214  defined between the spacer  180 , the outer surface of the second piston rod  190 , and an interior wall of the housing  104 . As in the first end  107 , the defined spaced region is smaller than the outer dimensions of the quad ring  210 , thereby creating an interference fit and compression of the fitted quad ring  210 . The quad rings  145 ,  210 , which as previously noted are preferably compressed into their respective cavities form seals for the hydraulic chamber  200  within the interior of the assembly housing  104 . A rear bearing  215  is housed within the spacer  180  to support the second piston rod  190 . 
         [0037]    The overall operation of the hydraulic buffer assembly  100  is further discussed with reference to  FIGS. 2 and 3 . The assembly  100 , as shown in section, is depicted in an initial or extended position according to  FIG. 2 . An axial load is applied or otherwise imparted to the clevis  116  (see arrow  191 , representative of the movement of the bolt (not shown) of the paint gun (not shown)) that causes the attached first piston rod  124  and the clevis  116  in unison to move toward the second end  112  of the assembly housing  104 . The first piston rod  124  axially advances through the front bearing assembly  135  wherein the orificed piston head  150  is also caused to move axially toward the second end  112  of the housing  104 . The orificed piston head  150  sequentially engages the glide ring  162  and seal retainer  170 , wherein the second piston rod  190  is axially advanced through the second end  112  of the housing  104  to the compressed position shown in  FIG. 3 . During compression, the glide ring  162  moves to seal against the front face of the piston head  150 , as shown in  FIG. 2 . The glide ring  162  acts as a check valve. 
         [0038]    The contained hydraulic fluid is moved during this part of the operation through the orifices  153  of the piston head  150 . Overall, the hydraulic fluid is first guided through a path through the defined annular passages  176  of the seal retainer  170  and around the outside diameter of the seal retainer  170 , through the inner opening  164  of the glide ring  162 . The fluid is then moved through the orifices  153 , but only as a result of the glide ring  162  having sealed against the front face of the piston head  150 , thereby sealing the annular gap formed on the piston head  150  between the outer surface of the piston head  150  and the inner surface of the housing  104 . At the end of the stroke, the seal retainer  170  engages the interior wall  107  of the housing  104 , as shown in  FIG. 3 , with an end of the second piston rod  190  outwardly extending from the second end  112  of the housing  104 . 
         [0039]    With continued reference to  FIGS. 2 and 3  and according to this embodiment, a restoring force can be provided to the herein described buffer assembly  100 . For example, a spring (not shown) can be configured to engage the end of the second piston rod  190  in order to drive the second piston rod  190  and the attached seal retainer  170  against the piston head  150  toward the first end  108  of the assembly  100 . Hydraulic fluid contained within the defined chamber  200  is moved around the annular gap and through the orifices  153  formed in the piston head  150  without the delay previously caused by the check valve (i.e., check valve is open) as the glide ring  162  engages the inner wall of the housing  104 . The hydraulic fluid is moved through the inner opening  164  of the glide ring  162  and then through the annular passage  176  of the seal retainer  170 , with the first piston rod  124  and the clevis  120  being returned to the initial position of  FIG. 2 . According to this embodiment, the overall stroke of the depicted buffer assembly  100  is about 0.120 inches, although this parameter can be suitably varied depending on the application and paint gun. As such, the clevis  116  can be quickly moved from the compressed position of  FIG. 3  to the initial extended position of  FIG. 2 , as aided by the opened check valve wherein the contained hydraulic fluid is more quickly moved to advance the hydraulic buffer assembly  100 . 
         [0040]    An exemplary representation of a buffer assembly  100  as used in a paint gun is shown schematically in  FIG. 4 , the paint gun  300  being shown more completely in  FIG. 5 . The buffer assembly  100  is extremely compact and therefore takes up little room. One preferred location of the buffer assembly  100  is shown in phantom in  FIG. 5 . With reference to  FIG. 4  and according to this schematic representation, the bolt assembly  304  of the paint gun  300  is translatably movable per arrow  318  within a defined chamber and biased by means of a bolt spring  308 . The bolt assembly  304 , according to this embodiment, is mounted in parallel with the buffer assembly  100  by means of a pivoting assembly  316 . According to this embodiment, one end of the pivoting assembly  316  is maintained in contact with a portion of the movable bolt assembly  304 . The remaining end of the pivoting assembly  316  is rotatably attached to the clevis end  116 ,  FIG. 2 , of the buffer assembly  100  and the contained movable piston assembly, see arrow  321 . A tension return spring  320  having one end operatively coupled to the buffer assembly  100  is configured for supplying the restoring force thereto. The remaining end of the tension return spring  320  and the bolt spring  308  are fixedly attached to structure within the paint gun  300 . 
         [0041]    With reference to  FIGS. 1-5 , the translatable movement of the bolt assembly  304  between its firing and return cycles creates corresponding movement of the attached pivoting assembly  316  and therefore the buffer assembly  100  between the initial extended position of  FIG. 2  and the compressed position of  FIG. 3 . Damping occurs during the compression of the buffer assembly  100 , while free flow of the hydraulic fluid occurs as the buffer assembly  100  is moved to the extended position as aided by the tension return spring  320 . As a result, the firing rate of the paint gun  300  upon depression of the trigger  330  can be effectively controlled. 
       PARTS LIST FOR FIGS.  1 - 5   
       [0000]    
       
           100  hydraulic buffer assembly 
           104  housing, assembly 
           105  interior, housing 
           107  interior wall, housing 
           108  first end, housing 
           109  opening 
           110  axis, housing 
           112  second end, housing 
           116  clevis or connecting member 
           117  shoulder, clevis end 
           120  center hole or opening 
           124  first piston rod 
           128  retainer 
           129  set screw 
           130  center opening, retainer 
           135  bearing assembly 
           137  recess 
           138  sealing ring 
           139  center opening, bearing assembly 
           141  recessed portion, bearing assembly 
           145  quad ring 
           150  piston head 
           153  orifices, piston head 
           154  center opening 
           158  narrowed diametrical section 
           162  glide ring 
           164  inner opening, glide ring 
           170  seal retainer 
           172  center opening, seal retainer 
           174  recessed portion 
           176  annular passage, seal retainer 
           180  spacer 
           184  center opening, spacer 
           190  second piston rod 
           191  arrow 
           194  opening, second piston rod 
           200  chamber, hydraulic 
           210  quad ring 
           214  fixed space region 
           215  rear bearing 
           300  paint gun 
           304  bolt assembly 
           308  bolt spring 
           316  pivoting assembly 
           318  arrow, movement 
           320  tension return spring 
           321  arrow, movement 
           330  trigger 
       
     
         [0090]    The invention is inclusive of combinations of the aspects described herein. References to “a particular aspect” (or “embodiment” or “version”) and the like refer to features that are present in at least one aspect of the invention. Separate references to “an aspect” or “particular aspects” or the like do not necessarily refer to the same aspect or aspects; however, such aspects are not mutually exclusive, unless so specifically indicated or as are readily apparent to one of skill in the field. The use of singular or plural in referring to “method” or “methods”, and various components of the herein described assembly and the like is not intended to be overly limiting. The word “or” is used in this disclosure in a non-exclusive sense, unless explicitly noted. 
         [0091]    This invention has been described in detail with particular reference to certain aspects thereof. It will be readily apparent and understood that variations, modifications, and combinations can be effected by a person of ordinary skill within the intended scope of the invention and in accordance with the following claims.