Abstract:
An engine with a valve suitable for containing compressed gas and expelling the same upon opening of the valve is provided. Upon application of sufficient force to an element of the valve, the compressed gas is released from the engine. In one embodiment, the engine is fitted with a reusable valve. In another embodiment, the engine includes an engine housing with a pop-out feature that indicates if the engine is critically overcharged. A method of implementing quality control schemes during the manufacture or production of the engine and its component parts is provided, as well as a method of filling the engine with a compressed gas.

Description:
RELATED APPLICATIONS  
       [0001]    This is a Continuation-In-Part application of U.S. patent application Ser. No. 09/834,476 filed Apr. 13, 2001, which is incorporated by reference herein in its entirety. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to an engine with a valve. More particularly, the invention relates to a gas-pressured engine with a valve.  
         BACKGROUND OF THE INVENTION:  
         [0003]    Typically, needle-less medication injectors use either an expansion spring or a compressed inert gas to propel the fluid medication (via a push rod plunger) through a small orifice (an injector nozzle) which rests perpendicular to and against the injection site. The fluid medication is generally accelerated at a high rate to a speed of between about  800  feet per second (fps) and 1,200 fps (approximately 244 and 366 meters per second, respectively). This causes the fluid to pierce through the skin surface without the use of a needle, resulting in the medication being deposited in a flower pattern under the skin surface.  
           [0004]    In a jet injector, if the inert gas is not quickly and properly expelled, fluid may be improperly injected, as with those devices employing a compression spring. Conventional disposable needle-less injectors, such as those shown in U.S. Pat. No. 4,913,699 to Parsons and U.S. Pat. No. 5,009,637 to Newman et al. utilize a gas-containing, breakable tube that is shattered or cracked open by a side mounted trigger. Difficulties arise in the need to maintain tight tolerances on the breakable member, since minor changes in thickness can dramatically effect the pressure needed to deploy the gas from the gas chamber of the device. In addition, the broken shards of the breakable member are ejected at high speed when the gas is expelled and these shards can occasionally jam between the plunger driver and the housing, thereby preventing proper operation of the needle-less injector. Attempts to prevent small shards from being formed would obviate some of this potential, but tend to make activation of the device more difficult.  
           [0005]    U.S. Pat. Nos. 6,080,130, 6,063,053, 5,851,198 and 5,730,723 describe needle-less injectors incorporating a gas power source, thus obviating some of the limitations inherent in compression spring injectors and addressing many of the concerns of conventional jet injectors. The injectors described therein have a pre-filled and self-contained compressed gas for providing pressure to inject medication into the skin surface of a patient without the use of a needle.  
           [0006]    Gas power sources for needle-less injectors that employ either pop valves or breakaway tab valves to release the inert gas stored in their respective gas chambers, however, may only be opened once, thereby presenting difficulty with regard to quality control testing measures. Additionally, in filling a gas power source with compressed gas, safety measures and a range of quality control features are important. For instance, if a gas power source is critically overcharged, it may rupture during or after filling with a compressed gas. A rupture may occur in storage or even during operation (e.g., during the administration of a needle-less injection). Such an event may result in substantial injury to the recipient of an injection or to an individual administering the same. Other undesirable results may occur when the engine is used in conjunction with a device other than a needle-less injector, including harm to an individual or damage to a device to which such an engine is in operable contact.  
         SUMMARY OF THE DISCLOSURE  
         [0007]    It is therefore an object of an embodiment of the instant invention to provide a gas-pressured engine that obviates, for practical purposes, the above-mentioned limitations.  
           [0008]    In one embodiment of the instant invention, an engine includes an engine housing and a valve. Compressed gas may be contained in the engine housing, and released upon an opening of the valve. Further, the engine housing may include a depression on one end; the depression imparting to the engine a “pop-out” safety feature, wherein, when the engine is critically overcharged, the depression may substantially invert or otherwise deform its shape to provide greater internal volume for the compressed gas. This feature may avoid an engine rupture and may also provide an external visual cue that the engine is critically overcharged.  
           [0009]    In another embodiment of the present invention, an engine is fitted with a reusable valve. The valve may contain a rubber head that is held against a fixed element of the engine such that depression of a trigger separates the head from the fixed element, releasing the compressed gas from the engine. A spring may be included in the valve to help maintain a proper airtight seal with the canister holding the compressed gas. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 illustrates an engine with a valve in a closed position in accordance with an embodiment of the instant invention. FIG. 1 a  illustrates a cross-sectional view. FIG. 1 b  illustrates a proximate end perspective view. FIG. 1 c  illustrates a cross-sectional view with a central axis.  
         [0011]    [0011]FIG. 2 illustrates a cross-sectional view of an engine with a valve in an open position in accordance with an embodiment of the instant invention.  
         [0012]    [0012]FIG. 3 illustrates a cross-sectional view of an engine with a valve in accordance with an embodiment of the instant invention. The engine housing includes a substantial deformation owing to it being critically overcharged.  
         [0013]    [0013]FIGS. 4 a - d  illustrate the engine housing of a needle-less injector in accordance with an embodiment of the instant invention. FIG. 4 a  is a side perspective view, FIG. 4 b  is a side cross-sectional view, FIG. 4 c  is a proximate end perspective view and FIG. 4 d  is a distal end perspective view.  
         [0014]    [0014]FIGS. 5 a - c  illustrate the valve body of a needle-less injector in accordance with an embodiment of the instant invention. FIG. 5 a  is a side perspective view, FIG. 5 b  is a side cross-sectional view and FIG. 5 c  is a proximate end perspective view.  
         [0015]    [0015]FIGS. 6 a - c  illustrate the closing ferrule of a needle-less injector in accordance with an embodiment of the instant invention, prior to the closing ferrule being mechanically fitted around a valve body and an engine housing. FIG. 6 a  is a side perspective view, FIG. 6b is a side cross-sectional view and FIG. 6 c  is a proximate end perspective view.  
         [0016]    [0016]FIGS. 7 a - d  illustrate the threaded valve stem guide of a needle-less injector in accordance with an embodiment of the instant invention. FIG. 7 a  is a side perspective view in partial cross-section, FIG. 7 b  is a side cross-sectional view, FIG. 7 c  is a proximate end perspective view and FIG. 7 d  is a distal end perspective view.  
         [0017]    [0017]FIGS. 8 a - c  illustrate the valve stem of a needle-less injector in accordance with an embodiment of the instant invention. FIG. 8 a  is a side perspective view, FIG. 8 b  is a side cross-sectional view prior to the distal end being shaped and FIG. 8 c  is a proximate end perspective view.  
         [0018]    [0018]FIGS. 9 a - b  illustrate the valve spring of a needle-less injector in accordance with an embodiment of the instant invention. FIG. 9 a  is a side perspective view in the relaxed state, FIG. 9 b  is a side perspective view in the compressed state.  
         [0019]    [0019]FIGS. 10 a - b  illustrate an engine with a valve operably interacting with another device, in accordance with an embodiment of the instant invention. FIG. 1O a  is a side cross-sectional view of an engine with a valve in the closed position, the engine interacting with a device. FIG. 10 b  is a side cross-sectional view of an engine with a valve in the open position, the engine interacting with a device.  
         [0020]    [0020]FIG. 11 illustrates a side, cross-sectional view of an engine with a valve interacting with a needle-less injector, in accordance with an embodiment of the instant invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]    As shown in the drawings for purposes of illustration, the invention is embodied in an engine with a valve. The engine may include various safety and quality control features, such as a pop-out feature that indicates if the engine is critically overcharged, and a valve that may be reused. The reusable valve allows an engine to be used more than once, and also provides a quality control feature in that the valve may be opened and closed prior to filling the engine with compressed gas. The engine and valve of the present invention may be used with a variety of devices, including, but not limited to, a needle-less injector (FIG. 11).  
         [0022]    For ease in describing the various elements of the instant invention, the following spatial coordinate system will apply thereto. As depicted in FIG. 1 c,  a central axis  1  is defined through the length of a gas-pressured engine. This central axis has one terminus  2  at the proximate end of the engine, defined as that end of the device through which gas is expelled during normal operation of the engine. The other terminus  3  of the central axis is at the distal end of the engine, defined as that end of the device opposite the proximate end. Thus, various elements of the device of the instant invention may be described with reference to their respective proximate and distal portions, as well as their central axes.  
         [0023]    An engine assembly  101  is provided in an embodiment of the present invention, as depicted in FIG. 1 a.  The engine assembly  101  may contain an engine housing  1000 , as depicted in FIG. 4. The engine housing  1000  is preferably constructed of a material impermeable to a compressed gas stored therein, and has a hollow interior chamber  1003 . Most preferably, the engine housing  1000  is comprised of stainless steel or a similar metal. A compressed inert gas is preferably stored within the engine housing  1000  prior to use. The most preferred gas is carbon dioxide, though other suitable gases may be employed, as well. In most preferred embodiments, the engine assembly  101  is overcharged (i.e., excess compressed gas is stored therein) to allow for use at variable altitudes without hampering its performance. This is to be distinguished from the instance in which the engine assembly is critically overcharged, which is the instance wherein the pressure inside the engine assembly is higher than a pressure threshold. An overcharged engine assembly may account for, e.g., variations in altitude, whereas a critically overcharged engine assembly presents a concern of engine rupture. An overcharged engine, as opposed to a critically overcharged engine, is preferred in accordance with an embodiment of the instant invention, as described above.  
         [0024]    The engine housing  1000  is preferably roughly cylindrical in shape, though alternate configurations may be utilized. Referring to FIG. 4, the engine housing  1000  may have a portion of wide diameter  1001  and a portion of small diameter  1002 , wherein the portion of small diameter  1002  is proximate to the portion of wide diameter  1001 . The distal end of the engine housing  1000  may contain a circular depression  1004 . The proximate end of the engine housing  1000  contains an opening  1005 , and in preferred embodiments, a closing ridge  1006  encircles the opening  1005 .  
         [0025]    The circular depression  1004  that may be included in the engine housing  1000  in an embodiment of the present invention may impart a “pop-out” safety feature to the engine. As noted above, an overcharged engine is preferred in an embodiment of the present invention, while a critically overcharged engine may present safety concerns. Therefore, in a preferred embodiment of the present invention, as depicted in FIG. 3, the circular depression  1004  may substantially deform when the engine is critically overcharged (i.e., the internal pressure of the engine assembly is greater than a pressure threshold).  
         [0026]    In a deformed state, the circular depression  1004  may take on any number of geometric configurations depending on, for example, impurities latent in the material used to form the engine housing or the magnitude of the overcharging. Thus, the substantially inverted configuration of the circular depression illustratively depicted in FIG. 3 is just one of a variety of potential configurations. By way of example, deformed configurations of the circular depression  1004  may be symmetrical or asymmetrical; may be centered about the central axis or disposed at a distance therefrom; or may include multiple deformations. Any such configuration may provide an external, visual indication that the engine is critically overcharged.  
         [0027]    The engine assembly  101  preferably further contains a valve body  1100 , as depicted in FIG. 5. The valve body  1100  is preferably roughly cylindrical in its overall shape, and more preferably resides at least partially within the engine housing  1000 . The valve body  1100  most preferably has a closing rim  1101  around its outer circumference that rests against the closing ridge  1006  encircling the opening  1005  of the proximate end of the engine housing  1000 . Most preferably, a closing ferrule  1200  is wrapped around both the closing rim  1101  and closing ridge  1006  to secure the valve body  1100  and engine housing  1000  to one another (see FIG. 1 a ).  
         [0028]    In a most preferred embodiment of the present invention, as depicted in FIG. 1 a,  the exterior surface of the valve body  1100  distal to the closing rim  1101  is cylindrical and substantially corresponds to a preferred cylindrical interior surface of the engine housing  1000  along the portion of small diameter  1002 . Most preferably, the small diameter of the engine housing  1000  is equal to or slightly greater than the diameter of the exterior surface of the valve body  1100 , thereby allowing the valve body  1100  to reside at least partially within the portion of small diameter  1002 .  
         [0029]    The closing ferrule  1200  is shown in FIG. 6 prior to its distal portion  1201  being mechanically bent around the closing rim  1101  and closing ridge  1006 . The proximate portion  1202  of the closing ferrule  1200  is of substantially the same diameter as the exterior of the valve body  1100 , such that bending the distal portion mechanically couples the valve body  1100  to the engine housing  1000 . In FIG. 1 b,  the distal portion  1201  of the closing ferrule  1200  is shown in the bent state. The valve body  1000  preferably has a depression  1102  around its circumference adapted to fit a gasket  1103  (shown in FIG. 1 a ). The gasket  1103  helps ensure that an airtight seal is maintained between the interior of the engine housing  1000  which contains the gas and the local atmosphere.  
         [0030]    Referring to FIG. 5, the interior of the valve body  1100  is preferably hollow and comprised of several distinct portions. The distal interior portion  1104  of the valve body  1100  may contain a screw thread engagement  1105 , preferably extending from the distal end of the valve body  1100  to the distal end of a first axial cavity  1106 . The first axial cavity  1106  may be bounded on its proximate end by a shoulder  1107  that separates this first axial cavity  1106  from a second axial cavity  1108 , which is preferably of smaller diameter than the first axial cavity  1106 . In preferred embodiments, the shoulder  1107  is an angled edge. Also in preferred embodiments, at least one valve stem guide  1109  protrudes from the wall of the second axial cavity  1108 . In a most preferred embodiment, there are at least three such valve stem guides  1109  that serve to substantially prevent the valve stem  1400  from moving in any direction other than along the central axis of the engine during an operation thereof  
         [0031]    In one embodiment of the present invention, the proximate end of a chamber  1110  preferably has at least one grip  1111  extending therefrom. Preferably, the at least one grip  1111  locks around another suitable element of a needle-less injector or other device to which the engine is in operable contact, as the gripping element  1112  is situated on the interior side of the grip  1111 . In alternative embodiments, however, the at least one grip  1111  may lock within another element as the gripping element  1112  may be disposed on the exterior side of the grip  1111 . In most preferred embodiments, there are two grips  1111  disposed opposite one another each of which contains a gripping element  1112  situated on the interior side of the grip  1111 . In these most preferred embodiments, the two grips  1111  are slid over and lock around a corresponding mechanical element of another device. The interlocking of grips  1111  with such a mechanical element may aid in mitigating the kickback associated with deploying the compressed gas stored in the engine assembly  101 . An example of this feature is illustratively depicted in FIG. 10 which illustrates an engine with a valve  101  of the instant invention interacting with another device  200  (FIG. 10 a  depicts the engine with a valve  101  in a closed position and FIG. 10 b  depicts the engine with a valve  101  in an open position).  
         [0032]    The valve body  1100  preferably further contains a threaded valve guide  1300 , as depicted in FIG. 7. The threaded valve guide  1300  is preferably cylindrical in shape and threaded around its exterior wall  1301 , such that it may be screwed into the distal interior portion  1104  of the valve body  1100  by interacting with the screw thread engagement  1105 . Most preferably, the threading on the exterior wall  1301  of the threaded valve guide  1300  extends along the entirety of the exterior wall  1301  from the distal to the proximate end of the threaded valve guide  1300 . The threaded valve guide  1300  may also contain a cylindrical interior cavity  1302  that is unobstructed at the proximate end. The distal end, however, is preferably partially covered with a valve stem guide pane  1303 . The valve stem guide pane  1303  preferably provides at least one vent  1304  allowing gaseous communication between the interior cavity  1302  of the threaded valve guide  1300  and the hollow interior chamber  1003  of the engine housing  1000  at the distal end of the threaded valve guide  1300 . Also preferably, the valve stem guide pane  1303  includes a hole  1305  at the central axis slightly larger in diameter than the valve stem  1400  that resides therein. Most preferably, the valve stem guide pane  1303  further includes a spring seat  1306  on its proximate surface that is comprised of at least one ridge  1307  that maintains the valve spring  1500  in proper position.  
         [0033]    The valve body  1100  preferably further contains a valve stem  1400 , as depicted in FIG. 8. The valve stem  1400  is preferably comprised of a substantially cylindrical rod  1401  having a proximate end  1402  which is flat and a distal end  1403  which is preferably pressed or hammer-forged. The distal end  1403  is shown after hammer-forging in FIG. 8 a and prior to hammer-forged in FIG. 8 b.  Most preferably, there is also included a spring ridge  1404  that extends radially from the rod  1401 , and a roughly conical valve head  1405  affixed to the proximate and exterior surfaces of the spring ridge  1404  as well as that portion of the rod  1401  immediately proximate to the spring ridge  1404 . Most preferably, the valve head  1405  is comprised of a rubber material such as semi-permeable, silicon-based or butyl-based rubber that is sufficiently malleable for use in accordance with the engine. In most preferred embodiments, the angle between the proximate surface of the valve head  1405  and the central axis is substantially similar to the angle of the shoulder  1107  located between the first axial cavity  1106  and second axial cavity  1108  of the valve body  1100 .  
         [0034]    The valve body  1100  may further contain a valve spring  1500 , as depicted in FIG. 9. The valve spring  1500  is preferably composed of wire and semi-conical in shape, wherein the proximate end  1501  is smaller in diameter than the distal end  1502 . The proximate end  1501  of the valve spring  1500  preferably rests against the distal surface of the spring ridge  1404  on the valve stem  1400 , while the distal end  1502  of the valve spring  1500  preferably rests against the proximate surface of the valve stem guide pane  1303  and is held in place radially by the spring seat  1306 .  
         [0035]    Furthermore, the valve of the instant invention may be repeatedly opened and closed without being destroyed (FIGS. 1 a  and  2 , respectively), thus it may be inspected for quality control determinations by opening and closing at least one time prior to the engine assembly  101  being filled with compressed gas.  
         [0036]    Moreover, the engine and valve of the present invention may be readily scaled up or down to any desirable proportion without significant variation from the illustrative configurations set forth herein. Such configurations may be readily ascertained without undue experimentation. For instance, the engine and valve may be made to a substantially large size to function in conjunction with heavy-scale mechanical equipment. Alternatively, the engine and valve may be made to a substantially small size to operate along with micro-scale devices.  
       EXAMPLE 1  
     Filling an Engine that Includes a Valve with a Compressed Gas  
       [0037]    An uncharged engine assembly includes a valve, and is not filled with compressed gas. The uncharged engine assembly is placed in a sealed, pressure-controlled environment, and the ambient pressure in the sealed environment is raised by the forced addition of N 2 . The heightened ambient pressure forces the valve of the engine into the open position, owing to the heightened pressure being relatively greater than the initial pressure within the engine housing. After the ambient pressure and pressure within the engine housing equilibrate (i.e., the pressure in the environment is substantially equal to the pressure within the engine assembly), the spring included in the engine provides a force differential that pushes the valve into the closed position. The ambient pressure in the sealed environment is then lowered, and the engine is ready for use.  
       EXAMPLE 2  
     Operation of a Gas-Pressured Engine with a Valve  
       [0038]    Prior to use, the engine assembly is checked for quality control purposes by opening and closing the valve, and thereafter the engine housing is filled with a suitable compressed gas. The circular depression on the engine housing is inspected to ensure no substantial deformation (i.e., the “pop-out” feature). When the valve stem is axially depressed relative to the remainder of the engine, the valve spring is compressed and the valve opens as the valve head is separated from the shoulder residing between the first and second axial cavities of the valve body. Compressed gas (previously stored in the engine housing, the interior cavity of the threaded valve guide and the first axial cavity of the valve body) may then rush through the gap created between the valve head and the shoulder. The gas rushes through the second axial cavity, past the valve stem guides, through the chamber and out the proximate end of the engine assembly.  
         [0039]    While the description above refers to particular embodiments of the present invention, it should be readily apparent to people of ordinary skill in the art that a number of modifications may be made without departing from the spirit thereof The accompanying claims are intended to cover such modifications as would fall within the true spirit and scope of the invention. The presently disclosed embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description. All changes that come within the meaning of and range of equivalency of the claims are intended to be embraced therein.