the present invention will now be described more fully hereinafter with reference to the accompanying drawings , in which a preferred embodiment of the invention is shown . this invention may , however , be embodied in many different forms and should not be construed as limited to the embodiment set forth herein . rather , this embodiment is provided so that this application will be thorough and complete , and will fully convey the true scope of the invention to those skilled in the art . like numbers refer to like elements throughout the figures . the illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments . the illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein . many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure . other embodiments may be utilized and derived from the disclosure , such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure . additionally , the illustrations are merely representational and may not be drawn to scale . certain proportions within the illustrations may be exaggerated , while other proportions may be minimized . accordingly , the disclosure and the figures are to be regarded as illustrative rather than restrictive . one or more embodiments of the disclosure may be referred to herein , individually and / or collectively , by the term “ present invention ” merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention or inventive concept . moreover , although specific embodiments have been illustrated and described herein , it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown . this disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments . combinations of the above embodiments , and other embodiments not specifically described herein , will be apparent to those of skill in the art upon reviewing the description . the abstract of the disclosure is provided to comply with 37 c . f . r . § 1 . 72 ( b ) and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims . in addition , in the foregoing detailed description , various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure . this disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim . rather , as the following claims reflect , inventive subject matter may be directed to less than all of the features of any of the disclosed embodiments . thus , the following claims are incorporated into the detailed description , with each claim standing on its own as defining separately claimed subject matter . the below disclosed subject matter is to be considered illustrative , and not restrictive , and the appended claims are intended to cover all such modifications , enhancements , and other embodiments which fall within the true scope of the present invention . thus , to the maximum extent allowed by law , the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents , and shall not be restricted or limited by the foregoing detailed description . in describing the preferred and alternate embodiments of the present invention , as illustrated in the figures and / or described herein , specific terminology is employed for the sake of clarity . the invention , however , is not intended to be limited to the specific terminology so selected , and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish similar functions . referring now to fig1 - 2 and 5 - 9 , it is instructive to reference prior art embodiments , as previously disclosed in commonly - owned u . s . patent application ser . no . 11 / 503 , 314 and u . s . patent application ser . no . 11 / 807 , 202 , wherein the presently disclosed trocar and cannula assembly 400 having improved conical valve 450 may include one or more features in common therewith . that is , prior art non - planar valves 150 and 150 ′ are first referenced and instructively described relative to use with cannula 40 and common features of cap assembly 130 shared with prior trocar system 120 and the presently disclosed trocar system 420 . thereafter , embodiments of improved conical valve 450 are described , with preferred particularity . in general , improved conical valve 450 and non - planar valves 150 and 150 ′ may each be used with cannula 40 . cap assembly 130 of prior art trocar system 120 , as well as of presently disclosed trocar system 420 , preferably comprises valve housing 132 , wherein valve housing 132 may have , for example , a substantially annular shape , with proximal end housing portion 171 , distal end housing portion 173 , and medial housing portion 175 . proximal end housing portion 171 preferably includes first opening 131 having a first opening diameter defined by portions of inner valve housing sidewall 177 and extending distally in a substantially axial direction inner valve housing sidewall 177 , forming first opening 131 , extends substantially axially downward toward a valve opening , referenced prior art valve opening 151 , 151 ′ of prior art valve 150 , 150 ′, respectively , or valve opening 451 of improved conical valve 450 . the upper portion of the first opening 131 can be rounded so as not to have any right angle edges at the first opening 131 , but with the resulting cross - section forming a substantially cylindrical first opening 131 extending along the same axis as that for the prior art valve opening 151 , 151 ′ or improved conical valve opening 451 . the proximal end housing portion 171 can also include an annular valve ring recess 179 for retaining the prior art valve 150 , 150 ′ or improved conical valve 450 . the distal end housing portion 173 can include a second opening 133 having a second opening diameter defined by a distal valve housing sidewall 181 extending in a substantially axial direction . the medial housing portion 175 can includes a first proximal valve housing inner perimeter surface 183 and a second distal valve housing inner perimeter surface 185 which can have a perimeter size or circumference the same or slightly larger than that of the first proximal valve housing inner perimeter surface 183 . cap assembly 130 may also include compression ring 136 positioned in valve housing 132 at a medially axial position between first and second openings 131 , 133 of valve housing 132 , abuttingly contacting axially facing distal surface 199 of valve ring 195 . compression ring 136 includes compression ring opening 137 , substantially aligned axially with first opening 131 of valve housing 132 to allow extension of the plurality of elongate tools therethrough . compression ring opening 137 can also be sized to allow at least portions of inner valve housing sidewall 177 and valve 150 , 150 ′ or 450 to extend therethrough . compression ring 136 also includes outer perimeter surface 217 having a radial diameter sized so that compression ring 136 substantially abuttingly contacts proximal valve housing inner perimeter surface 183 when positioned within valve housing 132 and includes annular flange 219 extending preferably into each one of the plurality of convolute recesses 411 . compression ring 136 is positioned to compress valve ring 195 , 195 ′ or 495 against an axially facing inner surface and an axially facing shoulder of proximal end housing portion 171 of valve housing 132 which together , along with a portion of first proximal valve housing inner perimeter surface 183 of medial housing portion 175 , form valve ring recess 179 and / or compress the valve ring 195 against first proximal valve housing inner perimeter surface 183 of medial housing portion 175 , to hold valve ring 195 in valve ring recess 179 to fixedly position the valve 150 , 150 ′ or 450 within valve housing 132 . that is , compression ring 136 is positioned so that proximal valve housing inner perimeter surface 183 , surfaces forming valve ring recess 179 , and annular flange 219 of compression ring 136 rigidly hold valve ring 195 , 195 ′ or 495 within valve housing 132 . annular flange 219 of compression ring 136 can include a plurality of notches 221 symmetrically positioned spaced - apart from each other so that each of the notches 221 aligns with and receives a separate one of the plurality of rib members 459 to thereby rotationally align the compression ring 136 with the valve ring 495 when positioned in contact therewith . alternatively , the annular flange 219 can include a plurality of separate spaced apart flanges ( not shown ) having a gap between each pair of flanges defining the notch 221 and aligned with the plurality of rib members 459 to thereby enhance positioning of the valve ring 195 . to further enhance positioning of the valve ring 195 , according to an embodiment of the valve housing 132 and valve ring 195 , the axially facing inner surface of the proximal end housing portion 171 of the valve housing 132 can include one or more protuberances 205 extending at least partially along the length of the valve ring recess 179 , and the proximal surface 197 of the valve ring 195 can include one or more recesses 206 or can deform to form a recess 206 , as illustrated , to receive the one or more protuberances 205 to thereby enhance positioning of the valve ring 195 within the valve housing 132 . cap assembly 130 can also include second valve 160 . second valve 160 is advantageously positioned adjacent second opening 133 of valve housing 132 , abuttingly contacting compression ring 139 . second valve 160 advantageously has annular flange portion 162 spaced axially from the valve ring of the first valve 150 , 150 ′ or 450 . annular flange portion 162 can have a radial diameter sized so that annular flange portion 162 substantially abuttingly contacts the distal valve inner housing perimeter surface 185 and axially facing distal surface of compression ring 136 adjacent compression ring opening 137 to enhance the positioning of second valve 160 within valve housing 132 . second valve 160 includes second valve opening 223 positioned within annular flange portion 162 and , when positioned within valve housing 132 , is substantially aligned axially with first and second openings 131 , 133 , of valve housing 132 to allow extension of the plurality of elongate tools therethrough . annular - shaped sidewalls 164 are connected to annular flange portion 162 and extend distally in a substantially axial direction when positioned in valve housing 132 . at least one pair of valve flaps 166 is connected to and extends inwardly from sidewalls 164 and flange portion 162 . sidewalls 164 , for example , can extend distally of the end of valve housing 132 so that flange portion 162 retains only portions of second valve 160 within valve housing 132 and yet slidably or in a spaced - apart relation have other portions which are positioned within proximal portion 48 of cannula body 42 . similarly , portions of the valve extension 452 and / or the valve opening 451 of the first valve 450 can extend within the proximal portion 48 of the cannula body 42 . the pair of valve flaps 166 has at least one opening or slit 168 along common peripheral edges thereof through which the tools 22 , 23 , 24 , 25 , can individually and separately extend . second valve 160 also advantageously can have ribs or rib members ( not shown ), e . g ., formed integrally therewith as a single piece , and connected to sidewalls 164 to reduce drag as will be understood by those skilled in the art . second valve 160 can also be advantageously impregnated with a lubricant such as an oil material to enhance performance thereof . it should be noted that the illustrated sidewalls 164 can be replaced with other forms of extension extending from annular flange portion 162 of second valve 160 . further , valve opening 168 can take other forms , such as an annular shaped opening or other known to those skilled in the art . second valve 160 , in general , and the portion of sidewalls 164 surrounding opening 168 , in particular , can be formed of a flexible material similar to that used in forming the first valve 450 . for example , the flexible material advantageously can include a silicon material coated in paralene to enhance the strength of valve 160 and to enhance sliding and / or sealing of the plurality of tools . in order to enhance positioning of second valve 160 , a proximal surface of annular flange portion 162 of second valve 160 can include an at least partially annular recess 227 or can deform to form recess 227 , as illustrated , to receive an at least partially annular protuberance 225 extending from a distal surface of compression ring 136 to thereby enhance positioning of second valve 160 at least partially within valve housing 132 . a distal surface of annular flange portion 162 of second valve 160 can further include a second valve annular - shaped recess 229 adapted to receive an axially extending annular - shaped flange 272 of proximal portion 48 of cannula 40 to thereby enhance positioning of at least part of proximal portion 48 of cannula 40 within valve housing 132 . cap assembly 130 can also include cap seal ring 138 positioned at least partially within valve housing 132 and having an axially extending flange 274 positioned to abuttingly contact a distal surface of annular flange portion 162 of second valve 160 when positioned in valve housing 132 . cap seal ring 138 can include a plurality of radially extending flanges 135 , each adapted to engage outer peripheries of a separate one of the plurality of radially extending flanges 34 of cannula 40 to slidably detachably connect valve housing 132 to cannula 40 . cannula 40 can also include an annular shaped axially extending flange adapted to engage annular - shaped recess 229 of second valve 160 to thereby enhance positioning of cannula 40 securely against second valve 160 when positioned in engagement with radially extending flanges 135 of cap seal ring 138 . improved conical valve 450 , as with prior art valve 150 , 150 ′, is advantageously fixedly secured to valve housing 132 . fig6 illustrates an exemplary construction process of a prior art cap assembly 130 , as instructive of the similar construction process of the presently disclosed cap assembly 430 . to provide secure sealing , prior art valve 150 ( or similarly improved conical valve 450 , as may be so read throughout this and the immediately following exemplary cap assembly construction process paragraphs ) is first inserted into valve housing 132 . then compression ring 136 , for example , coated with an ultraviolet bonding agent , is placed into valve housing 132 adjacent and abuttingly contacting valve 150 in a “ stacked ” fashion . following this , second valve 160 is inserted into valve housing 132 adjacent and abuttingly contacting compression ring 136 , and cap seal ring 138 coated with an ultraviolet bonding agent is placed into valve housing 132 and abuttingly contacting outer peripheries of second valve 160 . both compression ring 136 and cap seal ring 138 can be coated with an ultraviolet bonding agent along the outer peripheries thereof abuttingly contacting the inner peripheries of valve housing 132 . once each of the components is in its place , the entire cap assembly is placed in a compression system , wherein each component is compressed to its desired depth into valve housing 132 . at that point , an ultraviolet light is exposed to the ultraviolet bonding agent to cure the materials . the curing takes place in about 8 seconds . upon the completion of the curing , cap assembly 130 is formed as one unit . beneficially , second valve 160 can be readily removed and exchanged for a replacement . when constructing a trocar system 120 , cap assembly 130 is then abuttingly connected to cannula 40 . proximal end portion 48 of cannula body 42 has at least one valve housing mating portion 34 associated therewith and cap seal ring 138 positioned in valve housing 132 also has at least one cannula body mating portion or flange 135 associated therewith so that cap assembly 130 matingly attaches to cannula body 42 in a secured position and whereby movement of cap assembly 130 , e . g ., rotation , by a hand of a user releases , e . g ., unsecures or unlocks , the respective mating portions 34 , 135 for ready removal of cap assembly 130 by the user with the first and second valves 450 , 160 , and so that specimens , e . g ., tissue , can be readily removed from cannula body 42 without damage by the first and second valves 450 , 160 . the extraction of large tissue samples and / or gauze packs can be accomplished without removing cannula 40 from the area where various endoscopic procedures take place . as perhaps best shown in fig2 and 5 , the prior art valve 150 , 151 ′, as with improved conical valve 450 ′, can include valve body 155 , 155 ′ or 455 , respectively , positioned at least partially within valve housing 132 , axially aligned with the first opening 131 of the valve housing 132 . valve body 155 , 155 ′ or 455 includes proximal valve section 191 , 191 ′ or 491 , respectively , fixedly positioned entirely within valve housing 132 , and distal valve section 193 , 193 ′ or 493 extending axially from proximal valve section 191 , 191 ′ or 491 . these common general features relative to prior art valve 150 , 150 ′ and improved conical valve 450 are related to facilitate general understanding relative to common interaction within cap assembly 40 , but should not be understood to indicate similarity of specific structure or performance between prior art valve 150 , 150 ′ and improved conical valve 450 , or to impart any limitation to the presently disclosed improved conical valve 450 other than as specifically described herein . valve 450 has periphery valve section 456 connected to and extending radially outwardly from peripheries of the base of valve extension 452 . periphery valve section 456 includes valve ring 495 , defining an outer perimeter of valve 450 , and preferably has plurality of convolutes 458 , plurality of rib members 459 , and circumferential baffle 494 . plurality of rib members 459 each preferably extend radially at least a portion of the distance between peripheries of the base of valve extension 452 and valve ring 495 , preferably symmetrically positioned spaced - apart from each other . preferably , plurality of rib members 459 preferably extends between the base of valve extension 452 and circumferential baffle 494 . thus , the proximal valve section 191 or 491 includes valve ring 195 or 495 , respectively , positioned in the valve ring recess 179 ( fig2 ) or 479 of the valve housing 132 . referring now to fig1 , valve ring 495 has proximal surface 497 , distal surface 499 , inner perimeter surface 501 , and an outer perimeter surface 503 defining an outer perimeter of valve body 455 . proximal valve section 491 preferably has circumferential baffle 494 extending radially inwardly from inner perimeter surface 501 of valve ring 495 to outer sidewall 510 of plurality of convolutes 458 . proximal valve section 491 can include plurality of convolutes 458 , each having outer sidewall 510 extending from circumferential baffle 494 , first sidewall 507 extending axially and radially inwardly from outer sidewall 510 , and a second sidewall 509 extending axially from first sidewall 507 , substantially parallel to or slightly angled from inner perimeter surface 501 of valve ring 495 , and forming an inner radial periphery of proximal valve section 491 . proximal surface 498 and distal surface 500 of periphery valve section 456 are each further defined by two sub - elements surfaces , wherein first sub - element surface 502 of proximal surface 498 is defined in a first plane and proximate the inner perimeter of periphery valve section 456 , and second sub - element surface 504 of proximal surface 498 is defined in a second plane and proximate the outer perimeter of periphery valve section 456 . a similar , but opposing relationship exists between two sub - element surfaces of distal surface 500 , wherein first sub - element surface 506 of distal surface 500 is defined in a first plane and proximate the inner perimeter of periphery valve section 456 , and second sub - element surface 508 of distal surface 500 is defined in a second plane and proximate the outer perimeter of periphery valve section 456 . accordingly , neither proximal surface 498 nor distal surface 500 of periphery valve section 456 is flat . periphery valve section 456 may include circumferential baffle element 494 , wherein second sub - element surface 504 of proximal surface 498 and second sub - element surface 508 of distal surface 500 are components thereof . that is , circumferential baffle element 494 is preferably related to proximal valve section 491 of valve 450 , wherein circumferential baffle element 494 is defined in the second plane proximate the outer perimeter of periphery valve section 456 . proximal valve section 491 of valve 450 can also include plurality of convolutes 458 , each having outer sidewall 510 extending axially from the second plane and circumferential baffle element 494 to the first plane and first sidewall 507 . outer sidewall 510 , first sidewall 507 , and the second sidewall 509 of each of the plurality of convolutes 458 form a respective convolute recess 511 . the proximal valve section 491 can also include a plurality of rib members 459 , each radially extending from circumferential baffle element 494 to inner perimeter surface 501 of the valve ring 495 and symmetrically positioned spaced - apart from each other . the distal valve section 493 can extend axially from proximal valve section 491 and can include valve extension 452 extending axially from the plurality of convolutes 458 . the valve extension 452 can have a proximal end portion 512 substantially connected to a distal portion of each of the plurality of convolutes 458 , a distal end portion 513 , and a medial portion 515 connected to and extending therebetween . according to an embodiment of the valve extension 452 , medial portion 515 can have a substantially frusta - conical or other similar conical - form shape , as illustrated . the distal valve section 493 includes valve opening 451 positioned in distal end portion 513 of valve extension 452 , which can have , for example , an annular shape . the valve opening 451 is adapted to individually and separately receive therethrough any one of the plurality of different elongate tools ( not shown ) each having a different diameter so that when any one of the plurality of elongate tools is positioned through valve opening 451 , a septum - type seal is maintained between peripheries of distal end portion 513 of valve extension 452 surrounding valve opening 451 and outer peripheries of any one of the plurality of elongate tools when extending therethrough . as noted previously , the plurality of tools each have an elongate body for extending through valve housing 132 , valve opening 451 of valve 450 , and the cannula 40 . the plurality of convolutes 458 are each positioned between and connected to any two adjacent rib members 459 . according to an embodiment of the convolutes 458 , each convolute 458 can be in a selected biased position before and after each of the plurality of different elongate tools , individually and separately , extends through the valve opening 451 . according to an embodiment of the present invention , the combination of the convolutes 458 , circumferential baffle 494 and valve extension 452 allow for axial movement of the tools without a corresponding movement within valve opening 451 with respect to outer peripheries of the tools . the valve body 455 , in general , and the portion of valve extension 452 surrounding opening 451 , in particular , can be formed of a flexible material to provide the elastic range necessary to accommodate the plurality of elongate tools . according to an embodiment of valve body 155 , the flexible material advantageously can include a silicon material coated with paralene , available through various manufacturers , including dow corning corp ., to enhance the strength of the valve 450 and to enhance sliding and sealing of the plurality of tools . a method of forming a trocar system 420 , as constructed , for example , the valve 450 advantageously has a stretching or elastic range to readily accommodate , e . g ., auto - reduction , tools or other instruments having a diameter of about 5 millimeters to about 15 millimeters as understood by those skilled in the art while still maintaining pneumoperitoneum . the valve opening 451 of the valve body 455 has a diameter less than the diameter of each of the tools that extend through valve 450 so that a secured seal is provided around outer peripheries of each of the tools . the second valve 160 advantageously has this range as well , but individually can even have a greater range , e . g ., 1 millimeter to 13 or 14 millimeters . accordingly , with valve 450 and second valve 160 , in combination , the trocar system 420 advantageously can receive different diameter instruments without the necessity of switching cannulas or valve systems . embodiments of the present invention also include a method of using a trocar system 420 , as with prior art trocar system 120 , including the steps of providing a cap assembly 130 , which includes valve 450 , or 150 , as described above , and inserting a tool through the valve 450 , or 150 , and cap assembly 130 . during the insertion through improved valve 450 , circumferential baffle 494 , convolutes 458 and valve extension 452 flex so that valve body 455 extends distally by contact pressure from the tool and so that a distal end of the tool is guided through valve opening 451 . the circumferential baffle 494 and symmetric rib structure reinforces the movement of convolutes 458 and the recovery of convolutes 458 once the tool is extended through valve opening 451 . because valve 450 is constructed in a thin and relatively conical shaped profile , valve 450 functions like a thin elastic membrane that flexes inwardly and outwardly along a fairly wide range of tool positions , without requiring valve opening 451 to “ slide ” along the outer peripheries of the respective tool once positioned through valve opening 451 , and does not float or rotate in the valve housing 132 . this method also includes extending the tool through a cannula body 42 matingly connected to the cap assembly 130 at a proximal portion 48 thereof . the method further includes the steps of detaching the cap assembly 130 from the cannula body 42 and removing tissue or other specimen as understood by those skilled in the art from the cannula body 42 . because various types and diameters of tools can be used by medical personnel , embodiments of a valve advantageously allow one type of valve , cannula , or trocar system to be readily used for all of these various sizes and types of tools . as noted , valve body 455 , in general , and the portion of valve extension 452 surrounding opening 451 , in particular , can be formed of a flexible material to provide the elastic range necessary to accommodate the plurality of elongate tools . according to an embodiment of valve body 455 , the flexible material advantageously can include a silicon material coated with paralene , available through various manufacturers including dow corning corp ., to enhance the strength of valve 450 and to enhance sliding and sealing of the plurality of tools . because ease of insertion and removal of the instruments is an important aspect during use of cannula 40 , and because even small measures of improvement can translate into realized enhancement of performance , coatings and other measures directed toward improving lubricity can be advantageously supplemented , wherein a reduction in electrostatic adhesion between valve 450 and the plurality of tools can serve to further enhance the ease of insertion and removal . the relationship between frictional force and roughness is parabolic , as depicted in fig1 , wherein frictional forces are increased between both very smooth , as well as very rough surfaces , and wherein at the vertex of the parabola , a target roughness quality is represented that results in little or no frictional force . the smoothness of valve extension 452 , therefore , can be specifically adjusted relative to previously described valve extension 152 ′, such as seen in fig7 - 9 , wherein plurality of friction - reduction features 300 were defined , but , as will be further discussed , are presently improved . that is , prior valve body 155 ′, in general , and the portion of the valve extension 152 ′ proximate opening 151 ′ included plurality of friction - reduction features 300 to advantageously minimize electrostatic forces between instruments and the valve 150 ′. the plurality of friction - reduction features 300 was configured to increase roughness of valve extension 152 ′ in such a manner that movement toward the vertex along the demonstrated parabolic curve relating frictional force and roughness can be realized , wherein plurality of friction - reduction features 300 was comprised of plurality of protrusions 302 , defined on outer surface 304 and inner surface 306 of valve extension 152 ′, generally over an area defined proximate and between medial portion 215 ′ and distal end portion 213 ′ of valve 150 ′. the friction - reduction features 300 were defined proximate the apical end of the valve 150 ′ in anticipation of contact with the plurality of elongate tools extended therethrough , and were further defined on both opposing surfaces 304 - 306 in order that advantageous minimization of electrostatic forces may be realized also during contact between the valve body 155 ′ and the second valve 160 . the plurality of protrusions 302 were tear - drop shaped , to functionally improve the prior manufacturing process , as well as serving to reduce the resistive forces between the contact surfaces of an inserted instrument and the valve 150 ′ without compromise to the septum seal or to the inherent flexibility and adaptability of the valve 150 ′. referring now to fig1 - 14 , improved conical valve 450 preferably has plurality of closely and symmetrically spaced friction - reduction features 600 , wherein increased concentration and relative proximity of friction - reduction features 600 was empirically determined to enhance minimization of electrostatic forces between instruments and valve 450 . friction - reduction features 600 are preferably protrusions formed on inner and outer surfaces , 504 and 506 , respectively , of conical valve 450 , proximate distal end 413 and valve opening 451 . preferably , first circumferential row 602 of protrusions 604 is defined proximate valve opening 451 in a closely - spaced , essentially abutting conformation , whereafter second circumferential row 606 of protrusions 604 is defined in a position of greater distance from valve opening 451 relative to first circumferential row 602 , wherein the same total number of protrusions 604 is preferably defined in second row 606 as first row 602 , but given the increased diameter of conical valve 450 at the location of second row 606 relative to that of first row 602 , protrusions 604 of second circumferential row 606 are less closely - spaced than those of first circumferential row 602 . thereafter , further plurality of rows 608 are defined in similar fashion . the positioning of the protrusions 604 of each adjacent circumferential row 608 may also be juxtaposed , such that a radial twist pattern may be defined by the protrusions 604 about conical valve 450 proximate distal end 413 and valve opening 451 . protrusions 604 , as noted , may be formed in essentially any shape capable of maintaining the preferred functionality of creating additional space between valve 450 and an instrument inserted therein , and thereby reducing surface area for frictional contact therebetween . moreover , protrusions 604 may be formed according to a multi - shot liquid silicone rubber process , wherein liquid silicone rubber may be utilized for formation of valve body 455 and traditional thermoplastic elements may be utilized for formation of protrusions 604 , thus combining materials of differing coefficients of friction in a single molded part . in such manner , protrusions 604 may perform with action similar to that of ball bearing elements . a further improvement proximate distal end 413 of valve 450 relates to the definition of the plurality of friction - reduction features 600 definition on both inner surface 504 and outer surface 506 of the distal end 413 of valve 450 , wherein each of the plurality of protrusions 604 is preferably shaped as a round - tipped cone 610 , wherein the position and shape of friction - reduction features effectively and measurably enhances friction reduction . that is , kinetic friction between valve 450 and related instruments is advantageously minimized as valve opening 451 is deformed temporarily by contact pressure from the tool , wherein contact area between valve 450 and the instruments is reduced . moreover , elongation or other reactive force redirection by circumferential baffle 494 serves to minimize deformation of the valve opening as well . the friction - reduction features 600 , especially with circumferential baffle 494 , ribs 459 , and convolutes 459 , can reduce the resistive forces between the contact surfaces of an inserted instrument and valve 450 without compromise to the septum seal or to the inherent flexibility and adaptability of valve 450 of the present invention , wherein a broad endoscopic instrument diameter range , from about 5 mm to 15 mm diameter , can be successfully accepted . the friction - reduction features 600 are preferably defined proximate the apical end of valve 450 , in anticipation of contact with the plurality of elongate tools extended therethrough , and are further preferably defined on both opposing surfaces 504 and 506 in order that advantageous minimization of electrostatic forces may be realized also during contact between valve 450 and second valve 160 . each protrusion 604 is thus preferably shaped with a generally circular base and extending outward from inner and outer surfaces 504 and 506 , respectively , of valve 450 , to form cone 610 , preferably with a rounded tip 612 . this preferred shape also serves to facilitate the manufacturing process , wherein successful formation and ejection of valve 450 from a mold is achieved more readily . thus , while it is recognized that other shapes could be utilized , the preferred round - tipped cone shape is preferred . further , while the arrangement of plurality of protrusions 604 is depicted and described according to the preferred configuration , wherein a particular enhanced roughness quality is achieved , with measurable improvements over previous configurations , relative to frictional force , other arrangements could be utilized , including more rows , aligned rows , non - rows and / or an arrangement of protrusions with even closer relative proximity , even approaching or achieving an essentially solid configuration , such as an annular rib ; however , resulting modification to the roughness and / or related electrostatic nature of the surface could influence the achieved performance enhancement relative to the preferred configuration . while the invention has been described with respect to a certain specific embodiment , it will be appreciated that many modifications and changes may be made by those skilled in the art without departing from the spirit of the invention . it is intended , therefore , by the appended claims to cover all such modifications and changes as fall within the true spirit and scope of the invention . in particular , with respect to the above description , it is to be realized that the optimum dimensional relationships for the parts of the present invention may include variations in size , materials , shape , form , function and manner of operation .
a trocar and cannula assembly with improved conical valve that incorporates a plurality of ribs to restrict and / or otherwise influence valve movement , and a plurality of improved convolutes and bumps to enhance performance characteristics .