Abstract:
A compressed gas regulator for use in the medical, emergency and home health care fields is disclosed. The regulator includes a body having a rectangular aperture for receiving an industry standard post valve typically found on a high pressure gas tank. The regulator includes a mechanical attachment device for securing the regulator to the post valve. The mechanical attachment device, or knob, is cylindrical in cross-section and is hollow so that it may receive a portion of the regulator therein. The outer periphery of the knob includes a knurl pattern to aid in gripping the knob. The knob includes a threaded rod extending axially along the hollow interior of the knob. The threaded rod engages mating threads in a threaded aperture of the regulator body. Rotating the fastener urges the regulator into contact with the post valve, and a valve seat on the regulator provide a gas seal between the regulator and the post valve. The knob includes a torque limiting device that prevents over-tightening of the regulator on the tank, thereby preventing unintentional damage to the regulator.

Description:
FIELD OF THE INVENTION 
     This invention relates to gas flow control devices and, more particularly, to a compact, pressure regulated gas flow control valve. 
     BACKGROUND OF THE INVENTION 
     Precisely calibrated pressure reducing and gas-metering devices (regulators) are commonly used in the medical, emergency and home health care industries for delivering oxygen to patients in need thereof Most regulators are attached to a high pressure oxygen tank via standardized mechanical connections as set forth in the Compressed Gas Associations standards. 
     In the prior art, see FIG. 1, a “t-handle” is typically the mechanical fastener or attachment device of choice for securing the regulator to a “post valve”. The post valve is attached to a high pressure gas tank. The post valve provides a convenient and reliable mechanical attachment mechanism for securing a regulator to a gas tank. Metered gas flow is usually delivered to the patient via a resilient flexible hollow tubing or hose. The tubing is attached to the regulator by forcing the tubing onto a tapered fitting having ridges thereon that aid in retaining the hose on the fitting. 
     It is not uncommon for the resilient tubing to become wrapped around or tangled on the t-handle of the regulator. Such tangling of the hose is very inconvenient to users of such devices. In an emergency scenario, precious time may be lost in providing gas to a patient as a medical assistant attempts to disentangle the tubing from the t-handle. 
     Further, service failures of regulators are, at times, attributable to over-tightening of the t-handle by the user. Such a failure requires return of the regulator to the manufacturer for repair. 
     What is needed is an attachment mechanism or fastener for securing a regulator to a high pressure gas tank that minimizes the likelihood of ensnaring resilient hoses or tubing typically used in the medical and home health care industry to deliver oxygen to a patient. Further, the fastener should limit the torque that a user may impart to the threaded rod or shaft of the fastener to prevent inadvertent damage to the regulator when attaching the regulator to a source of high pressure gas, be the source of high pressure gas a high pressure gas tank or a distributed high pressure gas system in a hospital. 
     SUMMARY OF THE INVENTION 
     A gas pressure regulator with torque limiting attachment device, according to one aspect of the present invention, comprises a body having a first aperture therethrough sized to receive a substantially rectangular pressure tank post valve, the body further including a mounting aperture having machining threads formed therein and in fluid communication with the first aperture, an inlet passage in fluid communication with the first aperture and an outlet passage in fluid communication with the inlet passage, regulator means disposed in the outlet passage for reducing gas pressure presented at the inlet passage, the regulator means supplying regulated gas pressure at the outlet passage, a threaded rod having a proximate end, a distal end and external threads formed on the lateral external surface thereof, the external threads mating with the machining threads of the mounting aperture, the proximate end of the rod being rotationally inserted into the mounting aperture of the body to secure the body to a pressure tank, a disk attached to the distal end of the threaded rod at the radial center of the disk, the rod extending perpendicularly from one surface of the disk, and a hollow cylindrical member having an open first end, an open second end, and having an internal diameter sized larger than the body, and wherein the first end of the cylindrical member is disposed over and around the body and the second end of the cylindrical member is attached to the disk. 
     A compressed gas pressure regulator device, according to another aspect of the present invention, comprises a body having a first aperture therethrough sized to receive a substantially rectangular pressure tank post valve, the body further including a mounting aperture having machining threads formed therein and in fluid communication with the first aperture, an inlet passage in fluid communication with the first aperture and an outlet passage in fluid communication with the inlet passage, regulator means disposed in the outlet passage for reducing gas pressure presented at the inlet passage, the regulator means supplying regulated gas pressure at the outlet passage, a threaded rod having a proximate end, a distal end and external threads formed on the lateral external surface thereof, the external threads mating with the machining threads of the mounting aperture, the proximate end of the rod being rotationally inserted into the mounting aperture of the body to secure the body to a pressure tank, a hollow cylindrical member having an open end and a closed end, and having an internal diameter sized larger than the body, and wherein the open end of the cylindrical member is disposed over and around the body, and means for limiting torque disposed between and attached to the distal end of the threaded rod and the cylindrical member, the means for limiting torque transmitting no more than a predetermined amount of tightening torque from the cylindrical member to the threaded rod. 
     One object of the present invention is to provide an improved compressed gas regulation device. 
     Another object of the present invention is to provide a compressed gas regulator device that minimizes the likelihood of entangling gas hoses and the like in the device. 
     Still another object of the present invention is to provide a compressed gas regulator device that includes a mechanism for limiting the tightening torque the user may apply when attaching the regulator to a source of compressed gas such as a pressure tank. 
     These and other object of the present invention will become more apparent from the following description of the preferred embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front elevational view of a compressed gas regulator of the prior art. 
     FIG. 2 is a perspective view of a compressed gas regulator having a torque limiting attachment knob according to the present invention. 
     FIG. 3 is a front elevational view of the knob of FIG.  2 . 
     FIG. 4 is a cross-sectional side view of the dome knob of FIG. 3 looking the direction of the arrows labeled A. 
     FIG. 5 is a front elevational view of the dome knob assembly of FIG.  2 . 
     FIG. 6 is a front elevational view of another embodiment of the dome knob of FIG.  5 . 
     FIG. 7 is a partial cross-sectional view of the dome knob of FIG. 5 shown attached to a regulator body. 
     FIG. 8 is a front elevational view of the threaded stem shown in FIGS. 5 and 6. 
     FIG. 9 is a front elevational view of another embodiment of a dome knob with torque limiting features according to the present invention. 
     FIG. 10 is a partial cross-sectional view of the dome knob of FIG. 9 shown attached to a regulator body. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. 
     Referring now to FIG. 1, a compressed gas regulator  10  according to the prior art is shown. Regulator  10  includes a body  12  having a yoke portion  14 , a t-handle attachment device  16 , and a flow meter portion  18 . The flow meter portion  18  includes a flow adjustment knob  19 . T-handle attachment device  16  is rotationally inserted into a threaded aperture  17  in yoke portion  14 . Disposed internally within body  12  is a pressure regulator mechanism (not shown), well known in the art, that regulates gas pressure presented at valve seat  20 . The pressure regulator mechanism supplies pressure regulated gas to the flow meter portion  18 . Metered gas flow is supplied at hose fitting  15 . Flow meter portion  18  of device  10  is detachable (as is described in more detail in my copending application entitled Compressed Gas Regulator With Flow Control and Internal Gauge, Ser. No. 09/213,441, Filed Dec. 18, 1998), and regulator  10  may be used merely as a gas pressure regulation device without gas flow metering functionality. Yoke portion  14  provides a mechanism for connection of regulator  10  to a standard CGA (Compressed Gas Association) 870 compressed gas tank connection. A CGA 870 tank connection (not shown) is a substantially rectangular post with a compressed gas fitting on a lateral surface thereof (see my copending application Ser. No. 09/349,924 entitled High Pressure Gas Valve for an example of a CGA 870 tank connection). The CGA 870 tank connection is aligned into position by dowel pins  22  so that valve seat  20  aligns with a mating compressed gas fitting on the CGA 870 connection device. Valve seat  20  is urged into contact with the CGA 870 connection when t-handle  16  is rotated, which forces the CGA 870 connection toward valve seat  20  to create a leak proof gas seal therebetween. Pressure regulated and flow metered gas is delivered at hose fitting  21 . 
     Referring now to FIG. 2, a compressed gas regulator with torque limiting attachment knob  30 , according to the present invention, is shown. Compressed gas regulator  30  is comprised of substantially the same components as found in device  10 , including a body  32 , a yoke portion  34  for receiving a CGA 870 connection, a flow meter portion  36  having a flow adjustment knob  37 , dowel pins  39 , and valve seat  38 . Torque limiting attachment knob  40  replaces the t-handle of device  10  in this embodiment of the invention. Torque limiting knob  40  is attached to threaded rod  42 , as is shown in subsequent FIGS. 5,  6  and  7 . A hose fitting (not shown) identical in functionality to fitting  21  (FIG. 1) is attached to and extends outward from flow meter portion  36 . 
     Referring now to FIG. 3, an end view of torque limiting attachment knob  40  is shown. A plurality of semi-circular detents  44  are formed about the inner periphery of knob  40 . Cylindrical aperture  46  receives threaded rod  42  (see FIGS. 2 and 7) therein. Though the detents  44  are depicted as semi-circular in cross-section, it is contemplated that other geometric shapes, such as triangular, square, hexagonal, etc., are feasible alternatives to the semi-circular detents shown in FIG.  3 . Knob  40  is made of brass, anodized aluminum, steel, plastic or other suitable materials well known in the art. Preferably, aluminum is used in the construction of knob  40  to reduce the overall weight of device  30 . 
     Referring now to FIG. 4, a cross-sectional view of knob  40  of FIG. 3, looking in the direction of the arrows labeled A, is shown. Knob  40  is cylindrical in cross-section. Detents  44  are formed on the inner periphery of knob  44 . Aperture  46  includes three distinct diameters at  46   a ,  46   b  and  46   c . The larger diameter of aperture  46 , at  46   a , provides a countersunk shoulder or ridge into which nut  48  (shown in FIG. 7) is disposed. Likewise, a shoulder is formed at location  46   c  by the larger diameter of aperture  46  at  46   c , providing a surface against which threaded rod  42  rests. The diameter of aperture  46  at  46   b  is sized just large enough for threaded rod  42  to freely rotate when rod  42  is disposed therein. 
     Referring now to FIGS. 5 and 6, two different embodiments of a torque limiting attachment device, according to the present invention, are shown. In FIG. 5, knob  41  includes a lesser quantity of detents  44  versus knob  40  of FIG.  6 . Depending upon the manufacturing technique employed, it is more likely that knob  41  would be less expensive to manufacture as less machining would be required to produce a smaller quantity of detents  44 . Also shown in FIGS. 5 and 6 is resilient rod  50 . Rod  50  is made of spring steel, stainless steel, beryllium copper, resilient plastic, graphite composite or a suitable substitute therefor. Rod  50  is inserted through a transverse aperture  52  (shown in FIGS. 7 and 8) in threaded rod  42  before threaded rod  42  is attached to knob  40  or  41 . Rod  50  is deformed into a semi-circular form at its distal ends when threaded rod  42  is inserted into and attached to knob  40  or  41 . Rod  50  has an overall length greater than the inner diameter, measured at opposing detents  44 , of knobs  40  or  41 . 
     Referring now to FIG. 7, a more detailed partial cross-sectional view of the compressed gas regulator with torque limiting attachment device  30  is shown. Resilient rod  50  is inserted through aperture  52  in threaded rod  42 . Rod  50  is resiliently bent at its distal ends so that rod  50  and threaded rod  42  may be disposed within knob  40  as shown. The distal ends of rod  50  engage detents  44 . Threaded rod  42  is inserted through aperture  46  and attached to knob  40  by nut  48 . Slip washer  54  is placed between knob  40  and nut  48  to enable knob  40  to rotate with respect to threaded rod  42  when the rotational force imparted to knob  40  exceeds the surface friction between slip washer  54  and knob  40 . Slip washer  54  is preferably made from nylon, plastic, aluminum or steel. Shoulder  56  of threaded rod  42  abuts knob  40  when rod  42  is inserted into aperture  46  of knob  40 . A c-clip  57  is snapped onto threaded rod  42  to retain threaded rod on yoke  34 . 
     Referring now to FIG. 8, threaded rod  42  is shown in more detail. Rod  42  includes a transverse through hole or aperture  52 . Rod  50  is received into aperture  52 . Shoulder  56  is formed with a diameter larger than aperture  46  in knob  40  so that threaded rod  42  will abut knob  40 . Threaded end  58  includes threads that mate with nut  48  so that threaded rod  42  may be secured to knob  40  by nut  48 . The length of barrel portion  60  is slightly longer in dimension than the length of aperture  46   b  (see FIG. 4) in knob  40 . Slot  62  receives retaining c-clip  57  (see FIG. 7) so that threaded rod  42  cannot be removed from yoke  34 . 
     Operationally speaking, when a user rotates knob  40  to attach regulator  30  onto a compressed gas tank, a rotational force is imparted to threaded rod  42  by resilient rod  50  when rod  50  engages detents  44 . When knob  40  is rotated to tighten device  30  onto the gas tank, rod  50  interacts with detents  44  to prevent excessive torque from being transmitted from knob  40  to threaded rod  42 . The lateral surface of rod  50  will disengage detents  44  when the rotational force on knob  40  overcomes the frictional forces between the lateral surface of rod  50  and detents  44 , at which time rod  50  is resiliently deformed inwardly and the lateral surfaces at the distal ends thereof slide along the inner periphery of knob  40  between detents  44 . When knob  40  is rotated in the opposing direction, i.e. to remove threaded rod  42  from contact with a post valve, the semi-circular deformation of rod  50  causes the distal ends thereof to contact or “bite into” detents  44  at a near right angle so that the rotational torque imparted to threaded rod  42  is higher when knob  40  is rotated to disconnect regulator  30  from a post valve. The sharper the distal ends of rod  50 , the higher the torque transmitted from knob  40  through resilient rod  50  to threaded rod  42  during the regulator disengagement process. 
     Referring now to FIGS. 9 and 10, another embodiment of a compressed gas regulator with torque limiting attachment knob  70 , according to the present invention, is shown. In FIG. 9, resilient rod  50  is disposed in aperture  52  of threaded rod  42  prior to the attachment of threaded rod  42  to knob  70 . Rod  50  is deformed into a semi-circular form at its distal ends when threaded rod  42  is inserted into and attached to knob  70 . Rod  50  is sized so that it must be slightly deformed to fit within knob  70 . Four dowel pins  72  are disposed about the inner periphery of knob  70  and mechanically interact with rod  42 . Dowel pins  72  are sized so that they may be “press fit” into cylindrical apertures formed in knob  70 . 
     In FIG. 10, compressed gas regulator  74  is shown with torque limiting knob  40  attached to a regulator body  32 . The regulator  74  is comprised of substantially the same components as found in device  30 , and like number components are identical in function and form. Items and features depicted in FIG. 10 include yoke portion  34 , threaded rod  42 , nut  48 , resilient rod  50 , transverse aperture  52 , washer  54 , shoulder  56 , c-clip  57 , knob  70 , and dowel pins  72 . 
     Knob  70  is constructed of the same materials as knob  40 . Dowel pins  72  are preferably made from high carbon or stainless steel. 
     Operationally, the device shown in FIGS. 9 and 10 operates to limit rotational torque applied to threaded rod  42  when threaded rod  42  is advanced into yoke portion  34 . When rotational tightening forces applied to knob  70  exceed the static frictional surface forces that exist between rod  50  and dowel pins  72 , resilient deformation of rod  50  will then take place as rod  50  is rotated over and past dowel pins  72 . Thus, a torque limit is established to prevent “over-tightening” of knob  70  when regulator  74  is attached to a source of high pressure, such as a post valve (not shown) well known in the art. 
     It is contemplated that a circular cross-section semi-circular snap-ring (not shown) may be used to attach threaded rod  42  to knob  70  by forming opposing u-shaped channels in the adjoining cylindrical surfaces, at location  76  in FIG. 10, between rod  42  and knob  70  to receive the snap-ring therebetween. Such a snap-ring would allow rotation of knob  70  with respect to threaded rod  42  and eliminate the need for nut  48  and washer  54 , and the added machining step of forming an aperture in knob  70  within which nut  48  is disposed. 
     While the invention has been illustrated and described in detail in the drawings and foregoing description of the preferred embodiment, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.