Abstract:
A pump assembly for a penile implant is provided having a mechanism which prevents spontaneous inflation of the cylinders implanted within the patient. The preventative mechanism uses overpressure generated by the reservoir during unintentional compression to effectively seal the cylinders from unintended fluid flow. The prevention mechanism itself creates all necessary forces to prevent the undesired fluid flow to the cylinders. This is accomplished by incorporating appropriate mechanisms within the pump itself.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    This application is related to patent applications entitled “DIAPHRAGM BASED SPONTANEOUS INFLATION INHIBITOR IN A PUMP FOR AN INFLATABLE PROSTHESIS,” “SWITCH BASED SPONTANEOUS INFLATION INHIBITOR IN A PUMP FOR AN INFLATABLE PROSTHESIS,” and “PENILE PROSTHESIS PUMP WITH RELIEF VALVE” which were filed concurrently herewith. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    This invention generally relates to a pump for inflating a prosthesis and more particularly to a pump and valve assembly including pressure based mechanisms that inhibit spontaneous inflation of the prosthesis.  
           [0003]    One common treatment for male erectile dysfunction is the implantation of a penile prosthesis. Such prosthesis typically includes a pair of inflatable cylinders, which are fluidly connected to a fluid (typically liquid) reservoir via a pump and valve assembly. The two cylinders are normally implanted into the corpus cavernosae of the patient and the reservoir is typically implanted in the patient&#39;s abdomen. The pump assembly is implanted in the scrotum. During use, the patient actuates the pump and fluid is transferred from the reservoir through the pump and into the cylinders. This results in the inflation of the cylinders and thereby produces the desired penis rigidity for a normal erection. Then, when the patient desires to deflate the cylinders, a valve assembly within the pump is actuated in a manner such that the fluid in the cylinders is released back into the reservoir. This deflation then returns the penis to a flaccid state.  
           [0004]    With inflatable penile prostheses of current designs, spontaneous inflation of the cylinders is known to occasionally occur due to inadvertent compression of the reservoir, resulting in the undesired introduction of fluid into the cylinders. Such inadvertent inflation can be uncomfortable and embarrassing for the patient. This undesirable condition is further described below with reference to a particular prosthetic design.  
           [0005]    With reference to FIG. 1, a known pump and valve assembly  8  for use in a penile prosthesis includes a fluid input  10  that is coupled at one end to a reservoir (not shown) and to a housing  12  at its opposite end. Also connected to the housing  12  is a fluid output  14  which, in turn, is connected at its other end to a pair of cylinders (not shown). Linking the fluid input  10  and the fluid output  14  to each other is a common passageway  33 , which itself contains a valve assembly that is described in greater detail below. Common passageway  33  is also in fluid communication with a pump bulb  18  that is used to move fluid from the reservoir (not shown) to the cylinders (not shown) in order to inflate the cylinders. The valve assembly located within common passageway  33  includes a reservoir poppet  20  which is biased against a valve seat  24  by a spring  28  and a cylinder poppet  22  which is biased against a valve seat  26  by a spring  30 . The springs  28  and  30  are sized so as to keep the reservoir poppet  20  and the cylinder poppet  22  biased against each respective valve seat  24  and  26  under the loads that are encountered when the reservoir is pressurized to typical abdominal pressures.  
           [0006]    When the patient wishes to inflate the cylinders, pump bulb  18  is squeezed so as to force fluid from the pump bulb  18  into the common passageway  33 . The resulting fluid flow serves to reinforce the force from the spring  28  urging the reservoir poppet  20  against valve seal  24  while at the same time causing compression of the spring  30 , and thereby opening cylinder poppet  22 . As a result, the fluid travels out through fluid output  14  and into the respective cylinders.  
           [0007]    When the patient releases the pump bulb  18  a vacuum is created, thus pulling the poppet  22  back against valve seat  26  (aided by spring  30 ) and simultaneously pulling the reservoir poppet  20  away from its valve seat  24 , against the spring  28 . As a result, fluid from the reservoir is thus allowed to flow through the fluid input  10  and into the common passageway  33  passing around the reservoir poppet  20  and into the vacuous pump bulb  18 . Once the pump bulb  18  has been filled, the negative pressure is eliminated and the reservoir poppet  20  returns to its normal position. This pumping action of the pump bulb  18  and valve assembly is repeated until the cylinders are fully inflated.  
           [0008]    To deflate the cylinders, the patient grips the housing  12  and compresses it along the axis of reservoir poppet  20  and cylinder poppet  22  in a manner such that the wall  13  of the housing  12  contacts the protruding end  21  of the reservoir poppet  20  and forces the reservoir poppet  20  away from valve seat  24 . This movement, in turn, causes the reservoir poppet  20  to contact cylinder poppet  22  and force cylinder poppet  22  away from valve seat  26 . As a result, both poppets  20  and  22  are moved away from their valve seats  24  and  26  and fluid moves out of the cylinders, through the fluid output  14 , through common passageway  33 , through the fluid input  10  and back into the reservoir.  
           [0009]    Although the springs  28  and  30  are sized to provide sufficient tension to keep poppets  20  and  22  firmly abutted against valve seats  24  and  26  under normal reservoir pressures, it is possible that pressure that exceeds the force provided by the springs could be exerted upon the reservoir during heightened physical activity or movement by the patient. Such excessive pressure on the reservoir may overcome the resistance of the spring-biased poppets  20  and  22  and thereby cause a spontaneous inflation of the cylinders. After implantation, encapsulation or calcification of the reservoir may occur. This encapsulation or calcification of the reservoir. In particular, the encapsulation could lead to a more snugly enclosed reservoir, thus increasing the likelihood of spontaneous inflation.  
           [0010]    In previous attempts to reduce or eliminate the occurrence of spontaneous inflation, different types of spontaneous inflation preventing valves have been introduced into the pump and valve assembly. Such previous valves are intended to permit the positive flow of fluid to the cylinders only in those circumstances when the patient has forcibly manipulated the valve.  
           [0011]    Although such previous valve designs reduce the frequency of spontaneous inflation, several drawbacks do exist. For example, such valves are typically complex, requiring two-handed operation, which is a serious drawback to elderly or severely ill patients. Some spontaneous inflation preventing valves also require the application of excessive force in order to manipulate the valves; which may be too demanding for some patients. Furthermore, such valve designs may cause patient discomfort due to the valve size or shape, because of increase in the overall volume of the implant within the patient. This increased size can also lead to interference with the patient&#39;s normal bodily functions. Finally, such previous valve designs typically add undesirable cost to the device as well as increase the complexity of the surgical implantation procedure. As such, there exists a need to provide a prosthetic penile implant having a spontaneous inflation prevention mechanism that addresses the problems encountered in the prior art.  
         BRIEF SUMMARY OF THE INVENTION  
         [0012]    The present invention includes a penile pump having a dual poppet arrangement wherein the poppets act as check valves or flow valves. Each poppet is spring-biased against a valve seat, and under normal circumstances, only allows positive fluid flow when a pump bulb is operated, thus causing an increase in fluid pressure that is transferred to the inflatable cylinders. To prevent spontaneous inflation when an overpressurization occurs in the reservoir, the same reservoir pressure is utilized to seal the fluid output against itself or to seal one or both of the poppets against the valve seat. Thus, the fluid is prevented from reaching the cylinders and creating a spontaneous inflation. When the movement or activity generating the overpressure in the reservoir is released, the system should return to equilibrium. Even if overpressurization of the reservoir is occurring, the pressure generated by compressing the pump bulb will far exceed the level of overpressure. Thus, the poppets will open in the normal way, allowing fluid to flow to the cylinders. The use of the overpressure in the reservoir itself to prevent fluid flow to the cylinders can occur in a variety of formats.  
           [0013]    In still another embodiment, the reservoir poppet is actually coupled to an outer wall defining a portion of the fluid input. When an overpressurization in the reservoir occurs, this outer wall is forced to expand which simultaneously causes the reservoir poppet to be pulled firmly against the valve seat. This effectively prevents fluid flow from reaching the cylinders and causing a spontaneous inflation.  
           [0014]    In yet another embodiment of the present invention, the valve seat is provided with a flexible valve that cooperates with the first poppet to prevent spontaneous inflation, which could be caused by excessive pressure in the reservoir. Specifically, pressure in the reservoir and associated valve input is presented to the flexible valve and thus causing the valve to be further forced against the poppet, thus sealing off the input. When inflation is desired however, the negative pressure pulling the first poppet away from the valve seat will allow the desired fluid flow.  
           [0015]    In yet still another embodiment, a tapered poppet us utilized in conjunction with a tapered valve seat. Each of these tapers do not exactly match each other, thus providing variable reactions to pressure signals.  
           [0016]    In a further embodiment, a section of the reservoir poppet protrudes into the reservoir chamber. This protruding section of the reservoir poppet is coupled to the outer wall of the reservoir chamber. The poppet is coupled to the wall with a connecting spring that permits relative movement between the poppet and the outer wall. The tension of the spring is selected so that it approximates the forces generated by pressurized fluid acting on the wall of the reservoir chamber. However, the spring force is not so great as to prevent the vacuum generated by the pump bulb from opening the poppet. Thus, when the pump bulb is compressed and released, the vacuum forces generated are sufficient to unseat to the reservoir poppet despite its connection to the outer reservoir chamber wall.  
           [0017]    In yet still a further embodiment, a relatively large and powerful biasing spring is coupled with the reservoir poppet to exert a relatively large force against the reservoir poppet forcing it into a sealing or closed position. Due to the strong biasing forces of the spring, overpressurization forces generated in the reservoir chamber are insufficient to unseat the reservoir poppet. Simply using such a spring will make it difficult for the vacuum forces generated by compression of the pump bulb to unseat the reservoir poppet. To eliminate this problem, the face of the reservoir poppet, which forms a fluid-tight seal when the reservoir poppet is in a closed position, is made relatively large. That is, the diameter of the face approaches the diameter of the chamber containing the reservoir poppet. Thus, the vacuum forces generated will act over a larger surface area thereby exerting a larger degree of force, which permits the unseating of the reservoir poppet despite the opposing force of the biasing spring.  
           [0018]    Because it is difficult to fabricate a housing having a planar wall that interacts with the planar poppet face to form a sufficiently fluid-tight seal, the portion of the housing holding the reservoir poppet contains a pair of spaced lip seals. The position of the lip seal serves two distinct purposes. The first is to prevent fluid pressure generated during over pressurization of the reservoir from engaging a large portion of the poppet face, which would in effect defeat the added strength provided by the biasing spring. The outer seal is also provided so that when a vacuum force is generated, the vacuum cannot act on the front surface of the poppet face that would, in effect, hold the reservoir poppet in a closed position.  
           [0019]    In still another embodiment of the present invention, the reservoir poppet is configured with a throughbore at a rear portion of the reservoir poppet that is in fluid communication with a passageway and an outlet adjacent to the cylinder poppet. A sliding valve seal is positioned over this section of the reservoir poppet. The sliding valve seal is held against the back wall of the chamber by a spring positioned between the front face of the sliding valve seal and the back face of the suction poppet valve seal. The arrangement of the valve sleeve on the rear of the reservoir poppet is such that fluid is only able to flow through the throughbore and out of the outlet when the valve sleeve is positioned near the rear of the chamber and the front face of the reservoir poppet is firmly seated. In a reservoir overpressurization situation, the valve sleeve is again pressed against the rear of the chamber. However, the reservoir poppet is also forced backwards into the chamber, forcing the throughbore to be occluded by the valve sleeve. This prevents fluid from flowing towards the cylinder poppet, which could ultimately lead to spontaneous inflation.  
           [0020]    In still yet another embodiment, the portion of the housing between the cylinder poppet and the reservoir chamber has been modified. In addition, the reservoir poppet is provided with a unique configuration to interact with the housing structure. The reservoir poppet has a face, similar to the other embodiments, that is spring biased towards a matching valve seat. An annular ring is molded into the housing just behind (towards the cylinder poppet) the valve seat and is sized to interact with the face.  
           [0021]    The pump assembly of this embodiment has two states, activated and deactivated. In the activated state, the reservoir poppet is positioned so that the face is between the annular ring and the valve seat. When so positioned, the pump assembly functions as previously described with reference to the other embodiments. A compression of the pump bulb force the face against the valve seat and causes the cylinder poppet to open. A release of the pump bulb generates a vacuum which removes the reservoir poppet face from the valve seat and allows fluid to flow from the reservoir and into the pump bulb. Thus, the activated state is used when actively inflating the cylinders and while it is desired to maintain the cylinders in an inflated state.  
           [0022]    In the deactivated state, the reservoir poppet is positioned so that the face moves through the annular ring. In this position, the face will be between the cylinder poppet and the annular ring and the reservoir poppet spring will bias the face so that it abuts the annular ring. In other words, the face is displaced from the valve seat, and a gap exists between the valve seat and the annular ring. The stem of the reservoir poppet extends from the face towards the cylinder poppet. The stem is a cylindrical member having a generally V-shaped groove extending about its circumference near the middle of the stem. The stem interacts with a flexible conical lip seal molded within the housing. When in the activated state, the conical lip seal is positioned near the V-shaped groove so that fluid flow is essentially unhindered. When in the deactivated state, the conical lip seal is caused to engage the cylindrical portion of the stem. Thus, a fluid tight seal can be formed.  
           [0023]    When in the deactivated state, the reservoir poppet can be moved to engage and release the cylinder poppet, leading to a deflation of the cylinders. During this time, the conical lip seal continues to be located near the cylindrical portion of the stem; however, the flexible nature of the conical lip seal allows fluid flow in a direction from the cylinders to the reservoir. The pump assembly must be placed in the deactivated state to prevent spontaneous inflation. When in this state, the conical lip seal engages the cylindrical portion of the stem. If overpressure is generated, the reservoir poppet can be displaced towards the cylinder poppet. As this occurs, the increased fluid pressure levels force the conical lip seal to firmly abut the cylindrical portion of the stem, preventing increased pressure levels from reaching and displacing the cylinder poppet. Thus, spontaneous inflation is prevented.  
           [0024]    In most of the embodiments, the force generated by an overpressurization of the reservoir is used to prevent fluid flow into the cylinders. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]    [0025]FIG. 1 Is a side-sectional view of a penile pump according to the teachings of the prior art.  
         [0026]    [0026]FIG. 2 is a side-sectional view of a penile pump wherein the reservoir poppet has been attached to an outer wall of the reservoir chamber.  
         [0027]    [0027]FIG. 3 is a side, partially sectional planar view of the attachment mechanism connecting the reservoir poppet to the outer wall of the fluid input chamber.  
         [0028]    [0028]FIG. 4 is a side sectional view of housing for a penile pump having a tapered reservoir poppet and corresponding passageway, which plugs the fluid input during overpressure situation.  
         [0029]    [0029]FIG. 5 is a side sectional view of housing for a penile pump having relief areas, which expand during an overpressure situation and seal against the reservoir poppet.  
         [0030]    [0030]FIG. 6 is a side sectional view of the penile pump in FIG. 5, illustrated during an overpressure situation.  
         [0031]    [0031]FIG. 7 is a side sectional view of the penile pump in FIG. 5, illustrated during a compression of the pump bulb.  
         [0032]    [0032]FIG. 8 is a side sectional view of the penile pump in FIG. 5, illustrated during a reinflation of the pump bulb.  
         [0033]    [0033]FIG. 9 is a side sectional view of the housing of a penile pump having relief areas which expand during an overpressure situation, and a termination chamber which cooperates with the cylinder poppet during the overpressure situation.  
         [0034]    [0034]FIG. 10 is a side sectional view of a housing for a penile pump having a reservoir poppet coupled to the outer wall of the reservoir chamber via a connecting spring.  
         [0035]    [0035]FIG. 11 is a side sectional view of the penile pump of FIG. 10 during an overpressurization situation.  
         [0036]    [0036]FIG. 12 is a side sectional view of the penile pump of FIG. 10 when vacuum forces are generated by the pump bulb.  
         [0037]    [0037]FIG. 13 is a side sectional view of the penile pump of FIG. 10 when both poppets have been manually opened.  
         [0038]    [0038]FIG. 14 is a side sectional view of a housing for a penile pump wherein the reservoir poppet includes a relatively large biasing spring and a large diameter poppet face, which abuts the two-spaced lip seals.  
         [0039]    [0039]FIG. 15 is a side sectional view of a housing for a penile pump having a reservoir poppet that includes a slidable valve seal that selectively includes a throughbore leading to an outlet in the reservoir poppet.  
         [0040]    [0040]FIG. 16 is a side sectional view of the penile pump illustrated in FIG. 16 during a compression of the pump bulb.  
         [0041]    [0041]FIG. 17 is a side sectional view of the penile pump illustrated in FIG. 16 when no forces are being generated.  
         [0042]    [0042]FIG. 18 is a side sectional view of the penile pump illustrated in FIG. 16 when both poppets have been manually opened.  
         [0043]    [0043]FIG. 18A is a perspective view of an alternate embodiment of a poppet usable in the penile pump in accordance with the present invention.  
         [0044]    [0044]FIG. 19 is a side sectional view of a penile pump assembly including a conical lip seal and an annular ring that interact with a reservoir poppet having a grooved stem and an abutting face.  
         [0045]    [0045]FIG. 20 is a side sectional view of the pump assembly of FIG. 19 while the pump bulb is reinflating after compression.  
         [0046]    [0046]FIG. 20A is a side sectional view illustrating how the reservoir poppet may be spaced from the annulus to effect fluid flow.  
         [0047]    [0047]FIG. 20B is front planar view of an annulus with a plurality of spacers.  
         [0048]    [0048]FIG. 21 is a side sectional view of the pump assembly of FIG. 19 while the cylinders are being deflated.  
         [0049]    [0049]FIG. 22 is a side sectional view of the pump assembly of FIG. 19 while in a deactivated state, which serves to inhibit spontaneous inflation. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0050]    Referring to FIG. 1, a pump assembly is shown and generally referred to as  8 . The pump assembly  8 , as illustrated in FIG. 1, is essentially that of the prior art, but an understanding of the working elements of pump assembly  8 , as illustrated in FIG. 1, is beneficial to understanding the operation of each embodiment of the present invention. Generally, the pump assembly  8  will be implanted into the patient&#39;s scrotum. A separate fluid-filled reservoir (not shown) is implanted in some other portion of the patient&#39;s body, usually in the abdomen. Fluidly connecting the reservoir to the pump assembly  8  is fluid input  10  which will usually be a flexible silicone tube. A pair of inflatable cylinders (not shown) are usually implanted in the patient&#39;s corpus cavernosae and are fluidly connected to pump assembly  8  via fluid output  14 , which is also usually a flexible silicone tube.  
         [0051]    In general, when pump assembly  8  is actuated, fluid is drawn from the reservoir through the pump assembly  8  and pumped into the cylinders. During the inflation process and until released by the patient, the pump assembly  8  maintains the fluid pressure in the cylinders, thus keeping them in their inflated state. When deflation is desired, the patient manipulates assembly  8 , permitting fluid to transfer out of the inflatable cylinders and into the reservoir, thereby deflating the cylinders and returning them to a flaccid state.  
         [0052]    Pump assembly  8  generally includes a housing  12  usually formed of silicone. Attached to housing  12  is a pump bulb  18 , which includes a relatively large pump chamber  36 . Fluid input  10  is coupled to the housing  12  and empties into a reservoir chamber  16 . As such, fluid input  10  couples reservoir chamber  16  to the reservoir. A common passageway  33  is fluidly coupled to reservoir chamber  16  at one end of the housing  12 , and is fluidly coupled to fluid output  14  at an opposite end of the housing  12 . Similarly, the pump chamber  36  is fluidly coupled to the common passageway  33  via pump passageway  34 .  
         [0053]    Disposed within common passageway  33  is a reservoir poppet  20  which functions as a check valve. Reservoir poppet  20  is an elongated member having a contoured portion which abuts reservoir poppet valve seat  24  forming a fluid tight seal. A reservoir poppet spring  28  engages reservoir poppet  20  and biases reservoir poppet  20  against the reservoir poppet valve seat  24 . Also disposed within common passageway  33  and in line with reservoir poppet  20  is cylinder poppet  22 . Cylinder poppet  22  forms a second check valve within common passageway  33 . Cylinder poppet  22  is biased by cylinder poppet spring  30  against cylinder poppet valve seat  26  in a normal state, thereby forming another fluid tight seal within common passageway  33 . Reservoir poppet  20  is substantially longer than cylinder poppet  22 . A front end of reservoir poppet  20  extends into reservoir chamber  16 , in close proximity to an outer wall of housing  12 . Furthermore, the front end of cylinder poppet  22  is in close proximity to the rear end of reservoir poppet  20 . As such, the patient can manipulate both poppets  20  and  22  by compressing the wall of housing  12 . Compression of the housing  12  will cause the reservoir poppet  20  to compress reservoir poppet spring  28  thus displacing the reservoir poppet  20  from reservoir poppet valve seat  24 . This motion will also cause cylinder poppet  22  to be displaced from cylinder poppet valve seat  26  while compressing cylinder poppet spring  30 . When both reservoir poppet  20  and cylinder poppet  22  are displaced from their respective valve seats, fluid is allowed to freely flow between reservoir chamber  16  and fluid output  14 , and hence fluid is allowed to freely flow between the reservoir and the cylinders.  
         [0054]    During a majority of the time, pump assembly  8  will be in the configuration shown in FIG. 1. That is, both reservoir poppet  20  and cylinder poppet  22  are abutting their respective valve seats  24  and  26 , forming a fluid tight seal. When inflation is desired, pump bulb  18  is manually compressed by the patient. This forces the fluid in pump chamber  36  out through pump passageway  34  and into common passageway  33 , under relatively high pressure. Because of the location of pump passageway  34  with respect to the reservoir poppet  20 , this increased pressure causes reservoir poppet  20  to further abut reservoir poppet valve seat  24 . This increased pressure is more than sufficient to remove cylinder poppet  22  from its abutment with cylinder poppet valve seat  26 , by compressing cylinder poppet spring  30 . As such, the pressurized fluid is allowed to pass through a portion of the common passageway  33  and into fluid output  14 , where it eventually reaches an inflatable cylinder. When released, the pump bulb  18  expands back to its original configuration, creating negative pressure within pump chamber  36  and common passageway  33 . This negative pressure draws cylinder poppet  22  towards valve seat  26  and simultaneously pulls reservoir poppet  20  away from valve seat  24 . As such, fluid is drawn from the reservoir and into pump chamber  36  until the negative pressure is eliminated. Then, reservoir poppet spring  28  causes the reservoir poppet  20  to reseat itself against valve seat  24 .  
         [0055]    Repeated compression of pump bulb  18  eventually inflates the cylinders to a sufficient degree of rigidity for the patient. Once inflated, the fluid remaining in fluid output  14  is under a relatively high degree of pressure. This high pressure fluid aids cylinder poppet spring  30  in forcing cylinder poppet  22  against cylinder poppet valve seat  26  again forming a fluid tight seal and preventing fluid from within the cylinders from passing through (preventing deflation of the cylinders).  
         [0056]    When the patient desires deflation of the cylinders, the wall of housing  13  is manually compressed. This compression forces reservoir poppet  20  away from reservoir poppet valve seat  24  and simultaneously causes cylinder poppet  22  to be removed from cylinder poppet valve seat  26 . The pressurized fluid within the cylinders and fluid output  14  naturally returns to the reservoir via common passageway  33 . Furthermore, the cylinders can be manually compressed forcing out any remaining fluid. Once the cylinders are satisfactorily emptied, the patient releases the grip on housing  12 , thus allowing cylinder poppet  22  and reservoir poppet  20  to once again abut their respective valve seats  24  and  26 .  
         [0057]    As described above, pump assembly  8  (as shown in FIG. 1) works relatively well under normal circumstances. However, when the patient compresses the reservoir inadvertently through bodily movement, the pressure generated may be sufficient to remove reservoir poppet  20  and cylinder poppet  22  from their respective valve seats  24  and  26 , thus spontaneously inflating the cylinders. When sufficient force is generated against the reservoir (or a similar component) to cause the fluid pressure to exceed the resistive characteristics of poppets  20  or  22 , an overpressure situation has occurred. Of course, the only way to release this spontaneous inflation is to manually release the check valves.  
         [0058]    To date, it has been very difficult to monitor and determine the pressures generated in an overpressure situation since each patient exhibits unique individual characteristics. Furthermore, each spontaneous inflation may result from a very different physical act on the part of the patient. However, it appears that pressure generated by compression of the reservoir results in a fluid pressure of up to 3 pounds per square inch (1.361 kg/25.4 2  mm) but may be as high as 6-8 pounds per square inch (2.722 kg/25.4 2  mm). Conversely, compression of the pump bulb  18  will usually generate pressures on the order of 20 pounds per square inch (9.072 kg/25.4 2  mm).  
         [0059]    Referring to FIG. 2, a first embodiment of the present invention is illustrated. A fluid input  10  couples a reservoir to reservoir chamber  16 . Reservoir poppet  20  has been modified to include a T-shaped tip  70 . Tip  70  is secured to an outer reservoir chamber wall  72 . Tip  70  is secured to the outer reservoir chamber wall by one or more connecting bands  74 . Sufficient freedom of movement for reservoir poppet  20  is provided so that during normal operation reservoir poppet  20  can be dislodged from its abutment with reservoir poppet valve seat  24 .  
         [0060]    During an overpressure situation, the reservoir is compressed, pressurizing the fluid and directing it through fluid input  10  and into reservoir chamber  16 . Outer reservoir chamber wall  72  has been made sufficiently flexible so that when this occurs, reservoir chamber  16  is caused to expand due to the increased pressure generated. As outer reservoir chamber wall  72  expands, connecting bands  74  coupled with tip  70  pull reservoir poppet  20  tightly against reservoir poppet seat  24 . The overpressurization generated by the reservoir is used against itself to prevent fluid from reaching the cylinders and creating a spontaneous inflation.  
         [0061]    Referring to FIG. 3 a side partially sectional view is shown which helps illustrate the interior side of outer reservoir chamber wall  72 . Tip  70  of reservoir poppet  20  is secured at each end by a connecting band  74  which overlaps tip  70  and is interconnected with outer reservoir chamber wall  72 . Any interconnection of tip  70  or reservoir poppet  20  to outer reservoir chamber wall  72  is acceptable so long as during an overpressurization situation, reservoir poppet  20  is pulled against reservoir poppet valve seat  24  and during normal use sufficient flexibility is provided so that reservoir poppet  20  can be displaced from reservoir poppet valve seat  24  allowing the desired fluid flow.  
         [0062]    Referring to FIG. 4, a second embodiment of the present invention is illustrated. FIG. 4 illustrates the portion of housing  12  containing reservoir poppet  20  and cylinder poppet  22 . Reservoir poppet  20  is an elongated member that terminates in a nose  82 . A tapered reservoir passageway  84  is provided through a sidewall  80  located adjacent to fluid input  10 . Located at the junction of the sidewall  80  and reservoir passageway  84  is a flap  78  that is able to flex, with respect to sidewall  80 . Flap  78  is simply the terminus of sidewall  80  at the passageway  84 , and will optimally be offset by some angle from the remainder of the sidewall  80 .  
         [0063]    As illustrated in FIG. 4, reservoir poppet  20  is in a sealed position. That is, fluid is not able to pass from fluid input  10  through tapered passageway  84  and beyond, because reservoir poppet  20  is sealed against sidewall  80  at reservoir poppet valve seat  24  and is held in place by spring  28 . In addition, nose  82  of reservoir poppet  20  contacts flap  78 , providing a further seal. The remainder of passageway  84  is open between reservoir poppet  20  and sidewall  80 .  
         [0064]    In normal use, reservoir poppet  20  is pulled away from its sealed position by a vacuum created at pump passageway  34 . This allows fluid to pass from fluid input  10 , through passageway  84 , and then through common passageway  33  into pump bulb  18 . During a compression of pump bulb  18 , reservoir poppet  20  is further pressed against valve seat  24 .  
         [0065]    During an overpressure situation, the fluid pressure in the reservoir and hence within fluid input  10  will increase. This increased pressure is applied evenly within fluid input  10 , however flaps  78  are able to give in response to these forces. As such, flap  78  will be forced against a portion of reservoir poppet  20 . The shape of reservoir poppet  20  and passageway  84  are chosen so that as flap  78  is pressed against reservoir poppet  20 , a strong seal is formed. In other words, sufficient give is provided in sidewall  80 , particularly at and behind flap  78  (due to its shape and flexibility) so that increased pressure causes a fluid tight encasement of poppet  20  rather than a displacement of poppet  20 . Therefore, reservoir poppet  20  remains sealed and spontaneous inflation is prevented. While one specific configuration of this concept is shown in FIG. 4, it is to be understood that a wide variety and combinations of the disclosed teachings may be used while achieving the same result. The shape of the reservoir poppet  20 , passageway  84 , and the location and shape of flap  78  are extremely variable so long as these elements work together to form a fluid tight seal during an overpressure situation.  
         [0066]    Referring to FIG. 5, a third embodiment is illustrated. Reservoir poppet  20  is an elongated member that extends from common passageway  33 , through poppet passageway  92  and into fluid input  10 . As with many of the above embodiments, in one position the reservoir poppet  20  abuts reservoir poppet valve seat  24 . Similarly, reservoir poppet  20  is only expected to be removed from valve seat  24  during a re-expansion of a compressed pump bulb  18 . To prevent the removal of the reservoir poppet from valve seat  24  during an overpressure situation, relief area  90  has been formed within the housing  12 . Formation of relief area  90  creates a flexible valve  88 . Flexible valve  88  forms a part of the reservoir poppet valve seat  24 , and appears as shown in FIG. 5, under normal circumstances.  
         [0067]    [0067]FIG. 6 illustrates an overpressure situation where the pressure of the fluid in fluid input  10  and poppet passageway  92  is relatively high. Rather than forcing reservoir poppet  20  from valve seat  24 , this overpressure causes relief area  90  to expand; which in turn causes flexible valve  88  to even more firmly abut reservoir poppet  20 . Depending upon the particular arrangement chosen, such an expansion of relief area  90  may cause some compression of reservoir poppet spring  28 . In other words, reservoir poppet  20  is caused to move towards the cylinder poppet  22 . Such motion will normally allow a spontaneous inflation to occur. However, in this embodiment, it is the movement of valve seat  24  that moves reservoir poppet  20 , as such, a fluid seal is not only maintained, it is made stronger. To further support reservoir poppet  20 , nose  46  of cylinder poppet is located in close proximity to the rear of reservoir poppet  20 . As such, when expansion of relief area  90  causes a small amount of movement of reservoir poppet  20 , reservoir poppet  20  is caused to abut cylinder poppet  22 . Therefore, any further movement of reservoir poppet  20  requires compression of both reservoir poppet spring  28  and cylinder poppet spring  30 . This combination of spring forces provides a relatively high resistive force opposing further movement of reservoir poppet  20 , even during an overpressure situation. This combined with the expandable characteristics of relief area  90  prevents a spontaneous inflation from occurring. Of course, the relief area  90  can be fashioned to prevent such spontaneous inflation without causing the reservoir poppet  20  to engage cylinder poppet  22 .  
         [0068]    [0068]FIG. 7 illustrates a state where pump bulb  18  is being compressed, forcing fluid around cylinder poppet  22  and out through cylinder poppet output  32 . Simultaneously, reservoir poppet  20  is forced towards fluid input  10 , causing flexible valve  88  to collapse against the inner portions of relief area  90 . Once again, the strength of the seal at valve seat  24  is increased during such movement.  
         [0069]    Immediately after the state shown in FIG. 7 occurs, pump bulb  18  is released. As illustrated in FIG. 8, this creates a vacuum which pulls cylinder poppet  22  against cylinder poppet valve seat  26  and pulls reservoir poppet  20  away from valve seat  24 ; thus allowing fluid from the reservoir to flow into pump bulb  18 . Flexible valve  88  is created with sufficient rigidity to resist being forced against reservoir poppet  20  while fluid is flowing through poppet passageway  92  and into pump bulb  18 . Furthermore, the previous compression of flexible valve  88  against poppet  20  (FIG. 7) substantially evacuates relief area  90 . Therefore when reservoir poppet  20  is initially pulled from valve seat  24 , relief area  90  will remain in an evacuated state while fluid flow begins. The system is configured so that relief area  90  will not totally fill (and expand) with fluid and seal against reservoir poppet  20  until pump bulb  18  has been refilled. This can be done by making flexible valve  88  too rigid to allow such a seal to be formed in this state; providing for a sufficient amount of reservoir poppet  20  movement to prevent the flexible valve  88  from reaching poppet  20 , even when relief area  90  is completely expanded; or simply imparting sufficient rigidity in flexible valve  88  so that the time is takes to expand relief area  90  is greater than the time it takes to refill pump bulb  18 .  
         [0070]    [0070]FIG. 9 illustrates a fourth embodiment utilizing a combined solution to avoid spontaneous inflation. Namely, relief area  90  has been provided and works as described above. In addition, bypass passageway  38  has been provided which fluidly connects fluid input  10  to termination chamber  40 . Termination chamber  40  includes abutting wall  42 , which acts as a diaphragm when an overpressure situation occurs. These two mechanisms will act in concert to prevent a spontaneous inflation from occurring. One advantage of this arrangement is that nose  46  of the cylinder poppet  22  will be displaced towards the rear of reservoir poppet  20  via an expansion of termination chamber  40 . This force opposes the movement of the reservoir poppet  20 , in the opposite direction that is generated from an expansion of relief area  90 . In essence, the force generated by the overpressure is caused to directly oppose itself, which in turn prevents spontaneous inflation.  
         [0071]    Referring to FIG. 10, a fifth embodiment to the present invention is illustrated. Housing  12  includes a fluid input  10  that is in fluid communication with fluid output  14  through a reservoir chamber  16  and a common passageway  33 . Common passageway  33  is selectively occluded by a reservoir poppet  20  and cylinder poppet  22  which are both biased towards a closed position. A portion of reservoir poppet  20  is physically connected to a connection spring  100 . The opposite end of connection spring  100  is attached to a wall  13  of housing  12 . Connections to spring  100  are biased to maintain the configuration illustrated in FIG. 10.  
         [0072]    [0072]FIG. 11 illustrates what occurs during an overpressurization situation. As increased fluid pressure is generated, wall  13  in reservoir chamber  16  is caused to expand outward as indicated by the arrows. Since connection spring  100  is fixedly attached to wall  13 , the tension generated by expanding spring  100  serves to pull reservoir poppet  20  firmly against valve seal  24 , creating an even more fluid tight seal.  
         [0073]    Once pump bulb  18  has been compressed and released, vacuum forces are generated which unseat reservoir poppet  20 . This situation is illustrated in FIG. 12. Thus, despite an overpressurization situation wherein wall  13  is expanded outwardly and connection spring  100  is pulling against reservoir poppet  20 , the vacuum forces generated, are sufficient to unseat reservoir poppet  20  and allow fluid flow into pump bulb  18  (as shown by flow arrows A).  
         [0074]    When so desired, wall  13  is compressed causing reservoir poppet  20  to unseat itself and contact cylinder poppet  22  which, in turn, unseats that valve as well. Thus, fluid from the cylinders can be returned to the reservoir. This situation is illustrated in FIG. 13 and illustrates how the interaction of connection spring  100  and reservoir poppet  20  will facilitate this movement.  
         [0075]    Referring to FIG. 14, a sixth embodiment of the present invention is illustrated. A biasing spring  105 , exerting a large amount of force, is coupled to reservoir poppet  20  keeping it in its closed position. Because of the large amount of force being exerted, biasing spring  105  will be able to resist high forces generated during an overpressurization situation and, thus, preventing spontaneous inflation.  
         [0076]    Because biasing spring  105  is significantly stronger than those in the previous embodiments, it also makes it harder to open reservoir poppet  20  with the level of vacuum forces generated by the pump bulb  18 . To overcome this issue, poppet face  110  is made significantly larger than in the previous embodiments. That is, the surface area of poppet face  110  has a diameter that approximates the diameter of intermediate chamber  107 , which houses reservoir poppet  20 . Though the amount of pressure generated by the suction of release pump bulb  18  will be fixed, by increasing the surface area of poppet face  110 , the negative force generated will be greatly increased and will allow biasing spring  105  to be overcome.  
         [0077]    As illustrated, the portion of housing  12  in contact with poppet face  110  when reservoir poppet  20  is closed, is not simply a planar configuration. As a practical matter, it is too difficult to manufacture a planar surface which will flushly and repeatedly coact with a planar poppet face  110  to consistently form a fluid-tight seal. Instead, a pair of flexible lip seals is provided. That is, inner lip seal  115  and outer lip seal  120  are provided and define a recessed portion  125  between them. Outer lip seal  120  contacts an outer portion of poppet face  110  preventing suction forces from interacting with the rear portion of poppet face  110  and holding it in place during a refilling of pump bulb  18 . Inner lip seal  115  prevents fluid pressure generated during an overpressurization situation from acting against a majority of poppet face  110 , which would otherwise eliminate much of the benefit of having a larger biasing spring  105 . Lip seal  115  acting in conjunction with the forces generated by biasing spring  105  allows poppet face  110  to form a fluid-tight seal despite any irregularities in either poppet face  110  or housing  112 . During an overpressurization situation, pressurized fluid from reservoir chamber  16  interacts with only a very small area of poppet face  110 . The force generated will be insufficient to move biasing spring  105 , thus, reservoir poppet  20  will remain in the sealed position preventing spontaneous inflation.  
         [0078]    Referring to FIG. 15, a seventh embodiment of the present invention is illustrated. Once again, a reservoir poppet  20  and cylinder poppet  22  are provided to selectively occlude a common passageway  33  between a reservoir chamber  16  and a fluid output  14 . As in the previous embodiments, a front face  150  of reservoir poppet  20  abuts valve seal  24  to prevent fluid flow from reservoir chamber  16 . In this embodiment this occurs in two different situations. That is during a compression of pump bulb  18  (as illustrated in FIG. 16) and during an unused situation when no overpressurization is occurring (as illustrated in FIG. 17).  
         [0079]    Extending behind front face  150  is a rear section  137  of poppet  20 . At least a portion of rear section  137  is hollow and is in fluid communication with throughbore  140  (a plurality of throughbores  140  can also be provided). Outlet  145  forms a terminus of rear section  137  and is also in fluid communication with the hollowed out portion. A valve sleeve  130  slides over rear section  137  and is held in a spaced relationship from front face  150  by slide spring  135  which biases front face  150  away from valve sleeve  130 . The movement of valve sleeve  130  with respect to rear section  137  selectively seals and unseals throughbore  140 .  
         [0080]    As illustrated in FIG. 17, under normal conditions valve sleeve  130  is abutting a portion of housing  12 . Slide spring  135  biases front face  150  of poppet  20  against valve seal  24 . In this situation, it is front face  150  that prevents fluid flow from reservoir  16 .  
         [0081]    During an overpressurization situation, as illustrated in FIG. 16, the forces generated within reservoir chamber  16  serve to unseat front face  150  causing it to move away from valve seat  24 . To accomplish this, slide spring  135  must be at least partially compressed. In other words, overpressurization forces must be sufficient to compress slide spring  135  to cause this to occur. As front face  150  is unseated, rear section  137  moves through valve sleeve  130 , since valve sleeve  130  is pressed firmly against a portion of housing  12 . This action causes throughbore  140  to be occluded by valve sleeve  130 . Therefore, even though pressurized fluid is able to enter into chamber  107 , it is unable to pass through valve sleeve  130  and enter throughbore  140 . Consequently, pressurized fluid never reaches cylinder poppet  22  and is, therefore, unable to unseat it and cause spontaneous inflation.  
         [0082]    During compression of the pump bulb  18  (FIG. 16), pressurized fluid enters intermediate chamber  107  forcing front face  150  to firmly abut against valve seal  24 . At the same time valve sleeve  130  is pressed firmly against its respective portion of housing  12 . Since valve sleeve and front face  150  are spaced at their maximum distance, throughbore  140  is exposed and pressurized fluid from pump bulb  18  is able to pass through and unseat cylinder poppet  22  leading to an inflation of the cylinders.  
         [0083]    [0083]FIG. 18 illustrates how a manual release of a reservoir poppet  20  can unseat both the reservoir poppet  20  and cylinder poppet  22  allowing for deflation of the cylinders. Sleeve  130  is forced toward front face  150  by the pressure in the cylinders once cylinder poppet  20  is unseated.  
         [0084]    Referring to FIG. 18A, a poppet  20 ′ is disclosed that can alternatively be incorporated into previous embodiments of the invention in place of poppet  20 . The alternative poppet  20 ′ includes a plurality of flutes  145 ′ that loosely correspond in function to the output  145  discussed previously. Similarly, the lower, curved ends  140 ′ of the flutes  145 ′ loosely correspond in function to the throughbore  140  discussed previously.  
         [0085]    Referring to FIGS.  19 - 22 , an eighth embodiment of the present invention is illustrated. Housing  12  includes common passageway  33  that fluidly couples reservoir chamber  16  to fluid output  14  and is fluidly coupled to pump passageway  34 . Housing  12  also includes a tapered reservoir poppet valve seat  24  configured to interact with a similarly tapered front face  210  of reservoir poppet  20 . An annulus  205  is formed within housing  12  and is spaced away from, but proximate to, valve seat  24 . Annulus  205  is configured to provide an opening  207  that is slightly smaller than front face  210 . Annulus  205  is a semi-rigid portion of housing  12  that allows passage of front face  210  through opening  207  by moderate deflection. In other words, even though front face  210  is slightly larger than opening  207 , it can still be forced therethrough. (This relationship is more clearly seen by comparing FIG. 19 with FIG. 21.)  
         [0086]    Housing  12  also includes a conical lip seal  200 , which is positioned just forward of cylinder poppet  22 . Conical lip seal  200  is a flexible member that interacts with a stem  215  of reservoir poppet  20 . Stem  215  is generally cylindrical and includes a V-shaped groove  220  extending around its circumference. Groove  220  thus defines a medial stem section  225  that lies between groove  220  and front face  210 . Medial stem section  225  is generally cylindrical.  
         [0087]    Reservoir poppet  20  can be placed into three distinct configurations that define an activated state, a deactivated state, and a draining state. In the activated state, pump bulb  18  can be used to inflate the cylinders. Reservoir poppet  20  is also maintained in the activated state while the cylinders are to remain inflated. In the draining state illustrated in FIG. 21, the cylinders can be emptied. Reservoir poppet  20  is placed in the deactivated state during periods of non-use to prevent spontaneous inflation.  
         [0088]    [0088]FIGS. 19 and 20 illustrate pump assembly  8  in the activated state. Front face  210  is positioned between annulus  205  and valve seat  24 . When so positioned, reservoir poppet spring  28  biases front face  210  against valve seat  24 . If pump bulb  18  is compressed, the fluid pressure generated reinforces the biasing action of reservoir poppet  28 , and causes front face  210  to further abut valve seat  24 . At the same time, cylinder poppet  22  is unseated and fluid is forced into the cylinders. When reservoir poppet  20  is so positioned, V-shaped groove  220  is aligned with conical lip seal  200 . This effectively prevents conical lip seal  200  from interfering with fluid flow in either direction. That is, the configuration of conical lip seal  200  is such that it cannot effectively prevent fluid flow in a direction from cylinder poppet  22  towards reservoir chamber  16 . Fluid flow in the opposite direction is also unhindered (in the activated state) because groove  220  permits fluid pressure levels to increase “underneath” conical lip seal  200  (i.e., between lip seal  200  and stem  215 ), thus fluid flow is permitted from pump chamber  36  to the cylinders. FIG. 19 illustrates this configuration during a compression of pump bulb  18 .  
         [0089]    [0089]FIG. 20 illustrates the configuration of the components during a release of pump bulb  18 . The vacuum generated works with the biasing force of cylinder poppet spring  30  to cause cylinder poppet  22  to seal. The vacuum forces also cause front face  210  to be pulled away from valve seat  24 . This allows fluid to flow from reservoir chamber  16  into pump chamber  36 . While the vacuum forces are sufficient to unseat front face  210 , they are insufficient to cause it to pass through annulus  205 ; thus, back face  211  of reservoir poppet  20  abuts annulus  205  or (depending on the spring forces involved) is held between annulus  205  and valve seat  24 . In either case, fluid as able to flow into pump chamber  36 . After a number of compressions of pump bulb  18 , the cylinder will be inflated. While the cylinders are to remain inflated, pump assembly  8  is kept in the activated state.  
         [0090]    During a release of pump bulb  18 , the vacuum forces generated may be sufficient to cause back face  211  to seal against annulus  205 . If this occurs, the pump assembly may lock up and remain in this position. That is, pump bulb  18  will be at least partially compressed and the vacuum generated will be sufficient to keep reservoir poppet  20  sealed against annulus  205 , preventing fluid from moving from the reservoir to pump chamber  36 . All that need be done to relieve the vacuum is manually compress the sidewall to cause reservoir poppet  20  to unseat.  
         [0091]    This situation may be confusing to patients and they may not realize the nature of the problem. Thus, a modified annulus  205  (and/or a variation in reservoir poppet  20 ) can be provided to prevent the situation from occurring. Referring to FIGS. 20A and 20B, such a modified annulus  205  is illustrated. Annulus  205  includes a number of spacers  213  positioned about annulus  205  and facing valve seat  24 . Spacers  213  are positioned so that when rear face  211  is in contact with them, there is still a fluid path around reservoir poppet  20  and through annulus  205 . That is, there is never an opportunity for rear face  211  to seal against annulus  205 .  
         [0092]    The nature and number of spacers  213  can vary. Providing three spacers allows full support of rear face  211 . That is, rear face  211  is not caused to pivot by only being supported at one or two points. This pivoting action is not necessarily detrimental, and one or two spacers  213  could be utilized. More could also be utilized, so long as sufficient fluid flow is permitted. The actual size and shape of spacers  213  will depend upon the methods utilized to form them. Any size, shape and configuration is permissible so long as fluid flow sufficient to prevent the above described vacuum lock is permitted. Finally, spacers  13  could be attached to rear face  211  rather than annulus  205  to permit appropriate fluid flow.  
         [0093]    Alternatively, various other methods could be employed to achieve the same result. So long as fluid flow around rear face  211  and through annulus  205  is permitted, this potential problem is avoided. There are solutions other than providing spacers. For example, one or more grooves could be cut into rear face  211  to achieve the same result. Various other access ports or passageways could likewise be provided. Of course, these various techniques could be combined in any number of ways.  
         [0094]    After use, when the operator wishes to deflate the cylinders, the sidewalls of housing  12  are compressed. This forces reservoir poppet  20  to move from the activated position, past the deactivated position (as shown in FIG. 22) and into the draining state, by causing front face  210  to move through annulus  205  to the position illustrated in FIG. 21. Furthermore, this movement of reservoir poppet  20  causes it to engage cylinder poppet  22  and unseat it as well as moving front face  210  away from annulus  205 . Fluid is then able to flow from the cylinders into the reservoir.  
         [0095]    When the cylinders are satisfactorily deflated, housing  12  is released. Referring to FIG. 22, reservoir poppet spring  28  biases front face  210  against annulus  205 . As shown, reservoir poppet  20  is in the deactivated position. In this position, conical lip seal  200  engages medial stem section  225 , which is cylindrical in nature and approximates conical lip seal  200  in size and shape. Should a compression of the reservoir cause an overpressure situation, increased fluid pressure will force reservoir poppet  20  to be moved back from annulus  205  and allow reservoir pressure to enter intermediate space  300 . Without lip seal  200 , reservoir pressure would enter common passageway  33  and open cylinder poppet  22  causing spontaneous inflation. However, reservoir pressure will act on conical lip seal  200  causing it to firmly seal against medial stem section  225 , thus preventing fluid pressure from acting on cylinder poppet  22  and thus preventing spontaneous inflation.  
         [0096]    The operator must place pump assembly  8  in the deactivated state during periods of non-use to effectively prevent spontaneous inflation. When the operator desires to inflate the cylinders and pump assembly  8  is in the deactivated state, all that is required is a compression of pump bulb  18 . As pump bulb  18  is compressed, fluid pressure levels within intermediate space  300  are rapidly increased to relatively high levels. Conical lip seal  200  continues to prevent fluid flow therethrough (thus preventing an unseating of cylinder poppet  22 ); however, the higher pressures being generated are sufficient to force front face  210  through annulus  205 . Thus a compression of pump bulb  18  causes reservoir poppet  20  to move from the deactivated position to the activated position, from which the cylinders are inflated in the above described manner.  
         [0097]    Various embodiments have been shown and described to prevent spontaneous inflation. It is to be understood that though these embodiments have been shown and described in isolation, various features of each embodiment can be combined with the others to produce a variety of embodiments.  
         [0098]    While the present invention has been described with respect to a pump and valve assembly for a penile implant, the use of generated overpressure to seal a fluid aperture has many other applications within the scope and spirit of the present invention. For example, artificial sphincters utilize fluid pressure to maintain a body cavity or natural passageway in a closed or sealed state. When actuated, fluid pressure is released from the sphincter, causing the bodies&#39; passageway to open. As such, the fluid pressure generated could be used to assist the artificial sphincter in either state. Likewise, many other uses for an overpressure seal exist, both specifically within the field of medical devices and within the field of fluid/gas handling devices in general.  
         [0099]    Those skilled in the art will further appreciate that the present invention may be embodied in other specific forms without departing from the spirit or central attributes thereof. In that the foregoing description of the present invention discloses only exemplary embodiments thereof, it is to be understood that other variations are contemplated as being within the scope of the present invention. Accordingly, the present invention is not limited in the particular embodiments which have been described in detail therein. Rather, reference should be made to the appended claims as indicative of the scope and content of the present invention.