Patent Publication Number: US-2016245359-A1

Title: Piston head assembly for radio controlled cars shock absorber and method

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to shock absorbers and, more particularly in some non-limiting embodiments, to a piston head assembly for an R/C (Radio controlled) car shock absorber. 
     2. Background of the Invention 
     The sport of R/C vehicle racing is highly competitive. Professional drivers of R/C vehicles who race at the upper levels of the sport are well paid by sponsors. Engineers and hobbyists have worked for decades to constantly improve performance of R/C vehicles in every aspect of operation including motors, tires, weight, construction, shock absorbers, and the like. R/C vehicle enthusiasts are constantly searching for improved performance. Even small changes that can improve performance of lap speed by fractions of seconds are highly desirable and sought after. However, given the long term intense competition and efforts for improvements in this field, it is somewhat unusual to find improvements that reliably improve lap speed by one-half second or more. Devices that do provide performance improvements are often complex and inconsistent or prone to being less robust than desirable. Devices that provide improved performance in a manner that is readily repeatable and reliable are highly sought after. 
     Shock absorbers are commonly used in R/C vehicles and are commonly used in conjunction with springs in a variety of applications, particularly vehicles, bicycles, and the like, to control suspension movement by absorbing and dissipating energy during travel. Fluid-filled shock absorbers are one common type of shock absorber wherein a piston fastened to a piston rod travels through fluid in the bore of the piston cylinder. Another common type is similarly constructed, but with a gas instead of a fluid housed within the piston cylinder. 
     When a vehicle encounters a bump or uneven terrain, the suspension compresses during the compression stroke. After completing the compression stroke, the suspension responds by returning to its original position during the rebound stroke. Valves on the piston head restrict the flow of oil through the piston, causing more pressure to be created in front of the piston then behind it. The pressure differential creates the damping force needed to resist the uncontrolled movement of the piston and associated spring. 
     In the R/C car setting, shock absorbers provide a similar function but on a much smaller scale, which leads to unique problems specific to the R/C car application, including product materials, size difficulties, and the like. Tapered pistons and wafer pistons are just two of many alternatives that have been advanced to combat the problems outlined above. Examples of background patents and publications in the general area of shock absorbers include: 
     U.S. Pat. No. 4,620,619, issued Nov. 4, 1986, to Emura et al., discloses a variable-damping-force shock absorber such that the damping force determined through an orifice selected by an orifice adjuster according to the driver&#39;s preference can further automatically be increased during extension for improvement in road-holding ability and decreased during compression for improvement in riding comfort. The shock absorber according to the present invention comprises an annular member formed with an orifice and a disk valve disposed on top of the annular member. During extension, the disk valve is closed for allowing fluid to by-pass through an orifice of the annular member; during compression, the disk valve is opened for additionally allowing fluid to by-pass through the annular member. Further, since the various elements for adjusting the damping force are completely housed within the piston rod, it is possible to increase the stroke of the piston rod. 
     U.S. Pat. No. 4,775,038, issued Oct. 4, 1988 to Unnikrishnan et al., discloses a piston valving and seal mechanism for a fluid shock absorbing device. A piston is mountable on a piston rod of the device. The piston has an outer periphery, rebound chamber face and compression chamber face. A piston seal is movably mounted in a groove where the piston rebound chamber face and outer periphery meet. The seal is adjacent compression passages in the outer periphery. A seal retainer plate along the piston rebound chamber face with a backing spring bias the seal. The plate is raised from the rebound chamber face and includes passages, through the plate for fluid flow through the plate and into underlying recoil passages in the piston. The seal acts as a check valve for the compression passages. A separate recoil passage valve plate on the compression chamber face, with a backing spring, acts as a valve for the recoil passages. 
     U.S. Pat. No. 4,809,828, issued Mar. 7, 1989 to Nakazato, discloses a one-way damping valve mechanism in a hydraulic damper having a first hydraulic chamber defined in a cylinder, and a piston rod having an inner end on which there is mounted a piston slidably fitted in the cylinder, divides the first hydraulic chamber into a second hydraulic chamber and a third hydraulic chamber. The valve mechanism produces a damping force when the piston is moved in a prescribed direction to move working oil from the second hydraulic chamber into the third hydraulic chamber. The valve mechanism comprises a subvalve for defining a first hydraulic passage to generate a damping force when the piston moves at an extremely low speed in the prescribed direction, and a main valve for defining a second hydraulic passage to generate a damping force when the piston moves in a medium/high speed range in the prescribed direction. 
     U.S. Pat. No. 6,540,052, issued Apr. 1, 2003 to Fenn et al., discloses a Damping-valve body, in particular for a piston-cylinder unit filled with damping fluid, having separate passages for two directions of flow, at least some of the passages having an outlet opening that is at least partially covered by at least one valve disk. Each passage has a rib that extends radially, relative to a first direction of flow of the damping fluid, from a boundary wall of the passage and bears a valve support surface for the at least one valve disk. 
     U.S. Pat. No. 7,040,468, issued May 9, 2006 to Shinata, discloses a hydraulic shock absorber includes a cylindrical housing within which a piston assembly is slidably received. The piston assembly includes a piston element connected to a piston rod and adapted to divide an interior of the housing into compression and rebound chambers. The piston element has compression and rebound passages to provide fluid communication between the compression and rebound chambers. A valve assembly includes a first valve disc positioned on a lower side of the piston element, and a second valve disc retained on the first valve disc. The second valve disc includes apertures arranged in a circumferentially spaced relationship and are selectively openable and closeable by the first valve disc. A third valve disc is retained on the second valve disc and has notches arranged in a circumferentially spaced relationship. The notches cooperate with the apertures to collectively form ports. The ports are communicated with the compression chamber. A fourth valve disc cooperates with the second valve disc to sandwich the third valve disc so that restrictive orifices are defined in an outer end of the notches. Each of the ports has a cross sectional area greater than that of the restrictive orifices regardless of a relative angular position between the second and third valve discs. 
     U.S. Pat. No. 7,213,689, issued May 8, 2007 to Chang, discloses a shock absorber for a remote-controlled model car includes a sealing member fixed on the topside of a piston. The sealing member has two opposite flexible portions respectively matching with the flow-guiding holes of the piston, with flow gaps formed between the flexible portions and the upper outer sides of the piston. The flow gap, matching with the extent of an external force imposed upon the shock absorber, can be properly diminished or closed up. Each flexible portion is bored with a flow-adjusting hole smaller than and aligned to the flow-guiding hole of the piston for reducing the flow amount of liquid oil flowing through the flow-guiding hole. When pressed by different-extent external forces, the shock absorber can automatically adjust its buffering force to an excellent condition by adjustment of the flow-adjusting holes and the flow gaps. 
     U.S. Pat. No. 7,310,876, issued Dec. 25, 2007 to, May et al., discloses a method for producing a one-part piston body for a piston-cylinder arrangement, in particular a shock absorber piston, is disclosed. The method may include in a first step, pressing a green compact comprising a revolving web and longitudinal support webs from a sinterable metallurgical powder. In a second step, the green compact may be sintered to form a blank. In a third step, radially disposed stamping tools may be used to form, under material displacement, transverse grooves into at least a part of the support webs through cold deformation. In a fourth step, the blank provided with transverse grooves may be calibrated to its final form through pressing with calibrating tools. 
     U.S. Pat. No. 8,083,039, issued Dec. 27, 2011 to Vanbrabant, discloses a disc valve assembly for a shock absorber opens due to axial movement of a valve disc. The valve disc is biased against a valve body by a valve spring. The valve spring is designed to provide a circumferentially asymmetrical load biasing the valve disc against the valve body. The disc valve assembly can be used as a piston rebound valve assembly, a piston compression valve assembly, a base valve compression valve assembly or a base valve rebound valve assembly. 
     U.S. Pat. No. 8,235,188, issued Aug. 7, 2012 to Kais, discloses a damping element for a vibration damper that works with hydraulic fluid. The fundamental structure of the damping element includes a one-piece base body configured as a circular disk, which has a plurality of first flow-through openings, each having an entry cross-section in a first face side of the base body, as well as a plurality of second flow-through openings, each having an entry cross-section in an opposite, second face side of the base body, as well as circular valve disks on both face sides of the base body, which rest against a support surface of the base body, disposed in the center, and at least partially close off exit cross-sections of the flow-through openings. The exit cross-sections are surrounded by control edges, which form contact surfaces for the valve disks and project beyond the support surface as well as the entry cross-sections. The height of the control edges increases with an increasing radial distance from the center point of the base body in the form of a circular disk. According to the invention, the flow-through openings have a flow channel section that is preferably cylindrical and opens into a larger exit cross-section bordered by the control edges. 
     United States Patent Application No. 2013/0180813, published Jul. 18, 2013 to Moore, Jr., discloses a shock absorber configured to mount within a remote control vehicle. The shock absorber includes a cylindrical housing, a piston rod, and an acircular piston head. The piston head includes a plurality of substantially flat surfaces disposed on sides of the piston head that form bypass gaps between the piston head and the cylindrical housing. The acircular piston head includes a plurality of bypass apertures disposed through the piston head in an angularly asymmetrical configuration. The acircular piston head is generally octagon shaped. The acircular piston head includes a plurality of spaced arcuate edges sized to come in contact with an interior surface of the cylindrical housing. The shock absorber includes a plurality of bypass valves formed by cooperative operation of a shim coupled against the bypass apertures, such that fluid is permitted to flow through the bypass valves in a first direction and is restricted in a second direction. 
     United States Patent Application No. 2013/0180813, published Sep. 12, 2013 to Ericksen et al., discloses a vehicle damper comprising a fluid filled cylinder, a piston for movement within the cylinder, at least two fluid ports formed in the piston and at least one shim at least partially blocking the ports. In one embodiment, a fluid collection area is formed between the ports and the shim, the collection area permitting communication between fluid in the ports. In another embodiment, the piston includes at least one aperture constructed and arranged to receive a threaded bleed valve. 
     Many efforts have been made to improve the operation of all components of R/C vehicles including the relatively small size shock absorbers of R/C vehicles. Consequently, those skilled in the art will appreciate the present invention that addresses the above and other problems. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an improved R/C shock absorber that improves racing lap times. 
     Another possible object of the present invention is to provide an improved piston head assembly for R/C shock absorbers that improves racing performance. 
     Another possible object is to provide an improved piston head assembly for R/C shock absorbers with an increased rebound damping force. 
     Yet another possible object of the present invention is to provide a reliable and simplified piston for R/C shock absorbers which provides for a quick rebound damping force to reliably improve lap times. 
     A further possible object of the present invention is to provide an improved piston head assembly for R/C absorbers without unintended consequences to drivability. 
     These and other objects, features, and advantages of the present invention will become clear from the figures and description given hereinafter. It is understood that the objects listed above are not all inclusive, are non-limiting, and are only intended to aid in understanding the present invention, and do not limit the bounds of the present invention in any way. 
     Accordingly, the present invention, in one possible non-limiting embodiment comprises a piston head assembly for an R/C shock absorber. The R/C shock absorber comprises a piston rod, a piston cylinder, and fluid within the piston cylinder. 
     The piston head assembly comprises a piston head with a round periphery and defines a plurality of two-way holes therein that permit two-way fluid flow through the piston head when the piston head reciprocates in the piston cylinder. The piston head further defines at least first and second one way fluid flow valve holes in the piston head and at least one key slot. 
     A sealing member comprises a central portion and at least first and second valve members extend radially outwardly from the central portion. At least one key may extend from the sealing member. The at least one key and the at least one key slot are relatively positioned for cooperation to orient the first valve member to engage the first valve hole and the second valve member to engage the second valve hole to thereby form first and second one-way valves in the piston head. In another embodiment the sealing member is secured within a recess in the piston head. 
     The first and second valve members are flexible to open and close the first and second one-way valves in response to reciprocating movement of the piston head in the cylinder. As well, the first and second valve members are sufficiently resilient to engage and close the first and second one-way valves when the piston head is not moving in the piston cylinder. Accordingly the materials for the valve members are chosen with these requirements. 
     In one embodiment, the at least one key member may comprise greater than ten percent of a volume of the sealing member. The piston head may define a recess therein, with the sealing member being sized to fit inside the recess. In one embodiment, the flexible sealing member fits entirely within the recess. In another embodiment, the at least one key slot is defined within a boundary of the recess and comprises a depth in the piston head greater than a depth of the recess. 
     In one embodiment, the piston head may define a centrally positioned hole for connection to the piston rod. In one embodiment, two key slots are utilized with each of the two key slots being curved around the centrally positioned hole by an arc angle greater than sixty degrees. 
     In another embodiment, the first and second one-way valve holes in the piston head comprise first and second groups of valve holes. The first valve member engages the first group of valve holes and the second valve member engages the second group of valve holes. 
     In yet another embodiment, a method for manufacturing a piston head assembly for an R/C shock absorber is disclosed. The method for manufacturing a piston head assembly includes, but is not limited to, providing a piston head with a round periphery and defining a plurality of two-way holes therein that permit two-way fluid flow through the piston head when the piston head reciprocates in the piston cylinder. The piston head further defines first and second valve holes (or more valve holes) in the piston head and comprises at least one key slot (or more). The method further comprises providing a sealing member comprising a central portion and first and second (or more) valve members extending radially outwardly from the central portion. 
     Other steps may include providing at least one key extending from the sealing member. Other steps including providing that when the key is positioned within the key slot then the first valve member is oriented to engage the first valve hole and the second valve member is oriented to engage the second valve hole to thereby form first and second one-way valves in the piston head. The first and second valve members are flexible to open and close the first and second one-way valves in response to reciprocating movement of the piston head in the cylinder. 
     Another step may include providing the at least first and second valve members are also sufficiently resilient to engage and close the first and second one-way valves when the piston head is not moving in the piston cylinder. 
     The method may comprise providing the piston head defines a recess therein, the sealing member being sized to fit inside the recess and further providing the flexible sealing member fits entirely within the recess. 
     Another step may include defining the at least one key slot within a boundary of the recess and providing the at least one key slot comprises a depth in the piston head greater than a depth of the recess. 
     The method may further comprise providing the piston head defines a centrally positioned hole for connection to the piston rod, the at least one key slot actually comprises two key slots and each of the two key slots are curved around the centrally positioned hole by an arc angle greater than sixty degrees. 
     A further step may include providing the at least first and second one-way valve holes in the piston head comprise first and second groups of valve holes. The first valve member engages the first group of valve holes and the second valve member engages the second group of valve holes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the invention and many of the attendant advantages thereto will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is an exploded perspective view of a piston head assembly for an R/C shock absorber in accord with one possible non-limiting embodiment of the present invention. 
         FIG. 2  is an elevational view, partially in section, of a piston head assembly in an R/C shock absorber during a compression stroke in accord with one possible non-limiting embodiment of the present invention. 
         FIG. 3  is an elevational view, partially in section, of a piston head assembly in an R/C shock absorber during a rebound stroke in accord with one possible non-limiting embodiment of the present invention. 
         FIG. 4  is a top view of a piston head assembly for an R/C shock absorber in accord with one possible non-limiting embodiment of the present invention. 
     
    
    
     The above general description and the following detailed description are merely illustrative of the generic invention, and additional modes, advantages, and particulars of this invention will be readily suggested to those skilled in the art without departing from the spirit and scope of the invention. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to the drawings, and more particularly  FIG. 1 , there is depicted an exploded perspective view of piston head assembly  100  for an R/C shock absorber in accord with one possible non-limiting embodiment of the present invention. Generally speaking, piston head assembly  100  comprises sealing member  26  positioned on one side of piston head  10 , with both sealing member  26  and piston head  10  attached to piston rod  40  by fastener  30 . In this non-limiting embodiment, sealing member  26  is mounted on a side of piston head  10  opposite to piston rod  40 . Bolt stem  34  is inserted through washer  32 , sealing member hole  28 , central aperture  8 , and washer  42  before connecting with piston rod connection  44 . Fastener  30  may comprise various fasteners suitable for connecting with rod  40 , including, but not limited to screws, nuts, and the like. In this embodiment, washers  32  and  42  are placed between fastener  30  and sealing member  26 , and piston head  10  and piston rod  40 , respectively. In other embodiments, various alternative fastening arrangements may be utilized to secure piston head  10  to piston rod  40  consistent with the teachings of the present invention. In one embodiment, washer  32  is sized to cover sufficient of sealing member  26  within recess  18  to prevent rotation of sealing member  26  within recess  18 . Washer  32  is small enough to allow valve members  22  and  23  at the ends of sealing member  26  with sufficient flexibility to open and close one-way valve holes  14  and  15 . 
     In the present embodiment, piston or piston head  10  has a round periphery and comprises a plurality of two-way valve holes  12 , as well as first one way valve holes  14  and second one way valve holes  15 . Two-way valve holes  12  permit fluid flow in both directions through piston head  10 . First one way valve holes may comprise a group of one way valve holes as shown in  FIG. 1  where first one way valve holes  14  and second one-way valve holes  15  comprise two holes for each group. However, one hole or more than one hole could be utilized. The one-way valve holes may be smaller than the two-way valve holes if desired as perhaps best shown in  FIG. 4 . Piston head  10  will be discussed in further detail herein in regards to  FIG. 4 . Valve members  22  and  23  interact with one-way valve holes  14  and  15  to form one way valves. Valve members  22  and  23  are oriented by their position in recess  18  or by use of keys  24  to engage one-way valve holes  14  and  16 . 
     In alternative embodiments, more one way valves may be provided consistent with this disclosure to provide a desired rebound damping force. For example, additional valve members may extend from central body  20  of valve member  26 . Preferably, the valve members extend in a symmetrical way so that the forces produced by operation of the one-way valves do not cause tilting of piston head  10  during operation. For example, with three one-way valves, the valve members may be spaced sixty degrees apart. If four one-way valves are used, the valve members may be spaced apart by ninety degrees. 
     In one embodiment, recess  18  is sized to receive sealing member  26 . In one possible embodiment, recess  18  may but is not required to also comprise key slots  16 . In one embodiment, recess  18  comprises first recessed portion  4  and second recessed portion  6 . In a preferred embodiment, recess  18  has the same shape as sealing member  26  but is slightly larger to allow sealing member  26  to fit therein and to allow valve members  22  and  23  to cover and uncover holes  14  and  15 . 
     First recessed portion  4  and second recessed portion  6  extend radially outward in opposite directions from central portion  2 , and comprise one way valve holes  14  and  15 . Key slots  16 , the depth of which is shown better in  FIG. 2  and  FIG. 3 , can surround central portion  2  and engage key  24  to prevent axial movement of sealing member  26  during operation. In this embodiment, recess  18  is the same depth at all places except for key slots  16 . In another embodiment, key slots may not be utilized. 
     In an alternative embodiment, sealing member  26  could rest on the surface of piston head  10 . In that embodiment, only key slots  16  would extend into the face of piston head  10  to receive keys  26 , shown in  FIG. 2  and  FIG. 3 , with the shape shown in  FIG. 4 . The keys and key slots may be of different shapes. 
     Sealing member  26  comprises central body  20  with sealing member aperture  28  and first valve member  22  and second valve member  23  extending outwardly from body  20  in opposite directions. In a preferred embodiment, first valve member  22  and second valve member  23  are elongated oval shaped appendages that extend outwardly from the central portion that surrounds hold  28 . In other embodiments, different shapes are possible within the concepts described herein provided that first valve member  22  and second valve member  23  seat properly within first recessed portion  4  and second recessed portion  6 . In one embodiment, two keys  24  extend perpendicularly with respect to first valve member  22  and second valve member  23  (or axially as does fastener  30 ) and are curved to surround central portion  2  while fitting with key slots  16  with the outline thereof shown in  FIG. 4 . Keys  24 , when positioned in key slots  16 , maintain the sealing member  26  in the correct orientation so that valve members  22  and  23  abut one-way valve holes  14  and  15 . 
     It will be appreciated that significant forces are created during operation with the oil in the piston so that the size and shape of keys  24  and slots  16  being sufficiently large to keep the correct orientation of sealing member  26 . In one embodiment, the axial length of keys  24  and corresponding depth of key slots may be approximately the same or greater than the thickness of valve members  22  and  23  as perhaps better shown in  FIG. 2  and  FIG. 3 . Keys  24  may comprise a significant portion of the volume of sealing member  16 . For example keys  24  may comprise greater than 10 or 15 or 20 or 30 percent of the volume of sealing member  16 . 
     Keys  24  may be of different shape and construction. For example, keys  24  may extend radially outwardly from central body  20  like spokes or tabs and the corresponding key slots then may or may not be recessed more deeply than recess  18 . Accordingly, keys  24  and key slots  16  may be of numerous different configurations to thereby orient the valve members correctly with respect to the one-way valve holes. 
     When keys  24  are utilized, then sealing member  26  may be molded. Without keys, sealing member  26  may be flat and may be stamped or cut out. Accordingly, sealing member  26  may be constructed in different ways. 
     In one embodiment as shown, first valve member  22  and second valve member  23  fit flush and/or fully contained within recess  18  including first recessed portion  4  and second recessed portion  6 . First valve member  22  and second valve member  23  and are sufficiently resilient to engage one way valve holes  14  and  15  and close them off whereby first and second one way valve holes  14  and  15  are in the closed position preventing fluid flow when piston head  10  is not moving within piston cylinder  60 . Accordingly in one embodiment as shown, two normally closed one-way valve members are created. The thickness and/or resilience of the valve member will affect the response time of the valve so that thicker, less resilient, less flexible material of valve member reduces the fluid flow through the one way valves. 
     In one embodiment, a dedicated washer such as washer  32  hold the valve  26  and sufficient of the extension or arcs adjacent the central portion in the recess. If desired, washer  32  may be larger to cover greater portions of the valve member  26  to reliably maintain valve  26  in the correct orientation. The valve  26  is shaped such that it fits in precise arcs or extensions from the central portion to locate and position or orient the valve correctly so that ends  22  and  23  engage and disengage holes  14  and  16 . Past the arcs, the valves shape is relieved from the recess in the piston to facilitate free movement of the valve. The valves thickness is also a factor as to the depth of the recess and again, precise tolerances are held to keep the valve in place and provide free movement. We have also found that different durometer, flexibility, thickness, resilience of valves yields different results and is considered a tuning option. (softer valve=more oil flow, harder valve=less oil flow). 
     As shown in  FIG. 2  and  FIG. 3 , piston head assembly  100  is used within piston cylinder  60  with the piston cylinder operably attached to a spring (not shown). The spring and shock absorber assembly will be situated so that when the R/C vehicle encounters a bump or other movement of the vehicle, the spring will compress and piston rod  40  will push piston  10  down through the fluid within piston cylinder  60  only allowing fluid through two way valve holes  12 . This is called the compression stroke. Piston head  10  will then travel the opposite direction through piston cylinder  60  as the spring recoils to its normal operating position. This is called the rebound stroke. The movement of the shock absorber and spring is dependent on the force encountered by the suspension, and the damping force is selected to best keep the wheels on the ground during the suspension travel. 
       FIG. 2  is a partial sectional elevational view of piston head assembly in an R/C shock absorber  200  during the compression stroke in accord with the present invention. When an R/C car or vehicle encounters a bump or lands from a jump, for instance, the suspension reacts as depicted in  FIG. 2 . Piston rod  40  and piston head  10  travel within piston cylinder  60  as indicated by arrow  50 . Piston head  10  has a round shape which engages cylinder wall  82 , preventing fluid flow along the periphery of piston  10 . In this embodiment, sealing member  26  fits within recess  18  completely so as to be flush with the surface of piston head  10 . First one way valve member  22  engages first one way valve holes  14  to create a first one way valve and second one way valve member  23  engages second one way valve holes  15  to create a second one way valve. Fluid flows unimpeded through two way valve holes  12  as indicated by arrows  17  and  19 . However, first one way valve holes  14  and second one way valve holes  15  are blocked by first valve member  22  and second valve member  23 , thereby preventing fluid flow as indicated at arrows  52  and  54 . Therefore, the resistance to movement of piston head  10  in direction  50  is greater than the resistance will be in the opposite direction as discussed hereinafter in  FIG. 3 . 
     As discussed herein, first and second one way valves  14  and  15  comprise two holes each, while in other embodiments, only one hole may be provided for first and second one way valves  14  and  15 . In alternative embodiments, more than two holes may be provided for first and second one way valves  14  and  15 . The number of holes provided for first and second one way valves  14  and  15  is dependent on the rebound damping force desired for the particular application. 
     The size and construction of first valve member  22  and second valve member  23  must be large enough to prevent being drawn into first valve holes  14  and second valve holes  15 . The selected material and relative size of sealing member should be selected to be sufficiently flexible to move to open and close the one way valves in the oil typically used in R/C shock absorbers and at the speed of operation thereof. Further, in a preferred embodiment the sealing members are preferably selected of material that is resilient to close the valve members when the piston head is not moving to provide that the one-way valve so formed is normally closed. Sealing member  26  is preferably comprised of materials not easily torn to be suitable to be able to withstand the shock and wear of normal operation to prevent disintegration inside piston cylinder  60 . In one possible preferred embodiment, sealing member  26  could be constructed of a nitrile or neoprene rubber or other rubber or plastic materials. In a preferred embodiment, the material is selected to allow a range of operation at least anticipated ambient temperatures. 
       FIG. 3  is a partial sectional elevational view of piston head assembly in an R/C shock absorber  200  during a rebound stroke in accord with one embodiment of the present invention. In this figure, piston head assembly  200  is in the rebound stroke, meaning that the piston is attempting to return to its normal or original position after encountering a bump, landing, or other event that caused the suspension to compress as depicted in  FIG. 2 , by dissipating the energy stored in the springs working in conjunction with the shock absorber. In one embodiment, sealing member  26  fits flush within recess  18  with key  24  engaged fully with key slots  16  to prevent rotational movement of sealing member  26  as described herein. In other embodiments, sealing member  26  rests on top of piston  10  with key  24  engaged fully with key slots  16  and would perform the same as described herein. Piston  10  and piston rod  40  are moving within piston cylinder  60  as indicated by arrow  70 , opposite of the direction marked by arrow  50  shown in  FIG. 2 . 
     Fluid flows through two way valve holes  12  as indicated by arrows  35  and  37  just as described herein with regards to  FIG. 2 . However, in this embodiment first one way valve holes  14  and second one way valve holes  15  are not blocked by first valve member  22  and second valve member  23 , because the fluid flow is in the opposite direction compared to  FIG. 2 . The flow of fluid  80  through first one way valve holes  14  and second one way valve holes  15  as indicated by arrows  72  and  74  disengages first valve member  22  from first valve holes  14 , as well as second valve member  23  from second valve holes  15 , which allows fluid  80  to flow through piston  10  as indicated by arrows  76  and  78 . As discussed hereinbefore, first valve member  22  and first one way valve holes  14  act as a first one way valve, while second valve member  23  and second one way valve holes  15  act as a second one way valve for the rebound stroke. The first and second one way valves only allow fluid flow during the rebound stroke of the suspension. The increased flow of fluid  80  through piston  10  as indicated at arrows  76 ,  78 ,  35 , and  37  provides a quicker return to normal operation for piston head assembly  200  as compared to traditional piston head assemblies to better maintain the wheel in contact with the road on the rebound stroke of the shock absorber. 
       FIG. 4  is a top view of piston head assembly  10  for an R/C shock absorber in accord with one possible embodiment of the present invention. In a preferred embodiment, piston  10  is comprised of a plastic or hard composite material. In one embodiment, piston  10  has a diameter of less than one-half inch. In another embodiment, piston  10  may have a diameter greater than one half inch, but less than one inch. In a preferred embodiment, the thickness of piston  10  is less than one-eighth of an inch. The thickness of piston head  10  is equal to or less than the thickness of the stock piston head assemblies provided with the R/C vehicles. Central portion  2  defines aperture  8  for connecting piston head  10  and sealing member  26  to piston rod  40  utilizing fastener  30 . Key slots  16  curve around central portion  2  for receiving key  24  of sealing member  26 , and in a preferred embodiment, key slots  16  curve around central portion  2  by an arc angle greater than sixty degrees. In other embodiments, piston  10  may only comprise one key slot  16 . In a preferred embodiment, the depth of key slots  16  is greater than the depth of recess  18 , including first recess portion  4  and second recess portion  6 . Piston head  10  further comprises a plurality of two-way valve holes  12  surrounding the periphery to allow fluid flow in both directions in response to reciprocating movement of piston head  10  within piston cylinder  60 . 
     In a preferred embodiment, there are between no less than two and no more than eight of two way valve holes  12  present on piston head  10 . The number of two way valve holes  12  depends on the R/C application for which piston head assembly  10  is sought, as different R/C vehicles have varying number of valves on the piston head. In this embodiment, first one way valve holes  14  and second one-way valve holes  15  may comprise two holes for each group. In another embodiment, first one way valve holes  14  and second one-way valve holes  15  may comprise only one hole. One way valve holes  14  and second one way valve holes  15  may comprise one hole each, or more than one hole. Both one way valve holes  14  and second one way valve holes  15  have a thickness less than piston head  10  as they are located within recess  18  which provides a shorter distance for oil to travel through the one way valves formed. In another embodiment, two way valve holes  12  may also have a thickness, or length, less than piston head  10 . 
     As discussed hereinbefore, sealing member  26  is constructed of a nitrile or neoprene rubber in a preferred embodiment. The material selected for sealing member should be sufficiently flexible and resilient to both open and close the one way valves in the oil within the piston cylinder. Furthermore, in a preferred embodiment the sealing members are preferably selected of material suitable to withstand wear of normal operation to prevent disintegration inside piston cylinder  60 . 
     In operation, when the suspension encounters a bump the pistons damp movement of the springs during compression. Once past the bump, the increased flow through pistons during the rebound stroke allows faster movement of the springs to improve the ability of the tires to stay in contact with the surface. The one way valves are simply constructed to be highly reliable and effective. In a preferred embodiment, the valve members, central portion, and keys are molded or otherwise constructed as one piece of the same material. The relative size of two-way valve holes and one-way valve holes depends on the types of fluid in the piston, the spring strength, size of the piston, and such factors, as can be adjusted by hobbyists. The piston head assembly of the present invention is robust. Tests utilizing the present invention have shown, reliable improvement of lap speeds. The sealing member can be orientated by keys and/or by being secured within the recess in the head so that the valve members engage the one way valve holes. The piston head assembly of the present invention, if desired, can be sold utilizing standard sizes of piston heads without the need for different or specialized oil. Thus, the present invention is easily understood by users. If desired, sealing members with different durometers, flexibility, thickness, or the like, which factors affect the fluid flow, could be used by users to fine tune performance. 
     In general overview of the drawings, it will be understood that such terms as “up,” “down,” “vertical,” and the like, are made with reference to the drawings and/or the earth and that the devices may not be arranged in such positions at all times depending on variations in operation, transportation, mounting, and the like. As well, the drawings are intended to describe the concepts of the invention so that the presently preferred embodiments of the invention will be plainly disclosed to one of skill in the art but are not intended to be manufacturing level drawings or renditions of final products and may include highly simplified conceptual views and exaggerated angles, sizes, and the like, as desired for easier and quicker understanding or explanation of the invention. 
     One of skill in the art upon reviewing this specification will understand that the relative size, orientation, angular connection, and shape of the components may be greatly different from that shown to provide illuminating instruction in accord with the novel principals taught herein. As well, connectors, component shapes, and the like, between various housings and the like may be oriented or shaped differently or be of different types as desired. Many additional changes in the details, components, steps, and organization of the system and method, herein described and illustrated to explain the nature of the invention, may be made by those skilled in the art within the principle and scope of the invention. It is therefore understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.