Abstract:
A fuel cell includes a body, and a valve for releasing dispensable fluid from the body. The valve includes an elongated stem. A unitary member is secured to the body by its first end being secured to the stem. The unitary member includes a connector formed at a second end and a fluid conduit extending between the first and second ends. The connector is adapted for sealingly engaging a dispensable fluid inlet.

Description:
[0001]     The invention relates generally to a fuel cell for a combustion gas-powered tool. More particularly, the invention relates to a connector for connecting a valve of the fuel cell to the combustion gas-powered tool.  
       BACKGROUND OF THE INVENTION  
       [0002]     Fuel cells for a combustion gas-powered tool, and connectors for connecting a valve of a fuel cell to a combustion gas-powered tool, are known. U.S. Pat. No. 5,115,944 discloses a fuel cell of the type having an outer canister containing a pressurized propellant, an inner bag containing a dispensable fluid, and a valve for dispensing the fluid to a combustion gas-powered tool. When the valve is open, the pressurized propellant collapses the inner bag and forces the fluid to be dispensed from the inner bag through a valve stem of the open valve. U.S. Pat. No. 6,523,860 discloses an adapter system for connecting a valve of a fuel cell to a combustion gas-powered tool. The adapter system includes two components—an adapter and a molded insert. The molded insert is secured within a passageway in the adapter, then the adapter is placed onto the fuel cell such that a valve stem of the fuel cell is inserted into a first end of the molded insert. A base portion of the adapter includes barbs that engage a rolled seam of the fuel cell canister to secure the adapter onto the fuel cell. With the adapter secured to the fuel cell, the molded insert secured within the adapter, and the fuel cell valve stem inserted into one end of the molded insert, a fuel metering valve stem on the tool is inserted into a second end of the molded insert for abutting engagement with the fuel cell valve stem.  
         [0003]     It would be desirable to have a fuel cell having a simplified connector for engaging with a fuel inlet of a combustion gas-powered tool. It would also be desirable to have a connector that can be affirmatively connected directly to a valve stem of the fuel cell, and for the connector to be easily connected with a stem of a fuel metering valve in the combustion gas-powered tool so as to establish a leak resistant fluid conduit between the fuel cell and the fuel metering valve. It would also be desirable to have a connector which is permanently connected to a fuel cell and/or which can be easily affixed to the fuel stem.  
       SUMMARY OF THE INVENTION  
       [0004]     The above needs are met, and the shortcomings of prior art are overcome by the fuel cell connector of the invention. In particular, the invention provides a fuel cell having a unitary connector. The connector may have a first end that is secured directly to a valve stem of the fuel cell. The second end of the connector may be adapted to be easily engaged with a fuel metering valve in a combustion gas-powered tool, so as to establish a leak resistant fluid conduit between the fuel cell and the fuel metering valve.  
         [0005]     According to one embodiment, a fuel cell includes a body, and a valve having a stem for releasing dispensable fluid from the body. A unitary member is secured to the body by its first end being fixedly secured to the stem. The member has a connector formed at a second end, and a fluid conduit extending between the first and second ends, such that the connector is adapted for sealingly engaging a dispensable fluid inlet.  
         [0006]     The stem may extend parallel to a first axis, and the fluid conduit may extend parallel to the first axis. The connector may include an aperture that is circumscribed by a channel. The first end of the member may approximate a conical section, and the second end of the member may approximate a cylindrical section. The stem axis may be both parallel and collinear with the axis of revolution for the first and second ends. The connector may be a female fitting adapted for engaging a male inlet stem. The second end may include an outer flange and an inner flange spaced from, and circumscribed by the outer flange, the inner flange being adapted for engaging a fluid inlet stem. The fuel cell may be combined with a tool having a fluid inlet. The fluid inlet may include a male stem, wherein the female fitting is engaged with the male stem to provide a fluid tight seal.  
         [0007]     In another embodiment, a method for connecting a fuel cell to a tool having a dispensable fluid inlet is provided. The fuel cell includes a body containing a dispensable fluid, a stem and valve. The valve is opened by depressing the stem. The method includes the steps of providing a unitary adapter fixedly secured to an end of the stem, the adapter defining a fluid passageway extending between the stem and a connector formed at an end of the adapter; and engaging the dispensable fluid inlet with the connector so that there is a fluid-tight seal formed between the fuel cell stem and the dispensable fluid inlet.  
         [0008]     The engaging step may include inserting a male stem of the tool into an aperture of the connector and the aperture may include structure for press-fitting the male stem into the aperture. The press-fitting step may include forcibly inserting an end of the inlet stem beyond a ridge provided on the adapter.  
         [0009]     Additional features and advantages of the invention will be set forth or be apparent from the description that follows. The features and advantages of the invention will be realized and attained by the structures and methods particularly pointed out in the written description and claims hereof as well as the appended drawings.  
         [0010]     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation without limiting the scope of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]     The accompanying drawings, which are included to provide a further understanding of the invention, are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the invention and together with the description serve to explain the principles of the invention. In the drawings:  
         [0012]      FIG. 1  is a perspective view of a preferred embodiment of a fuel cell and a connector incorporating the principles of invention.  
         [0013]      FIG. 2   a  is a cross-sectional view of the connector of  FIG. 1 .  
         [0014]      FIG. 2   b  is a top view of the connector of  FIG. 1 .  
         [0015]      FIG. 2   c  is a bottom view of the connector of  FIG. 1 .  
         [0016]      FIG. 3  is a partial cross-sectional view of the fuel cell and connector of  FIG. 1 , and a metering valve of a combustion gas-powered tool, incorporating the principles of invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]     A fuel cell connector of the invention provides a one-piece member which connects a fuel cell to a valve stem of a metering valve in a combustion gas-powered tool. When connected, a fluid-tight seal may be established between the fuel cell contents and the tool without the use of additional fitting structure. A lower portion of the connector member may be fixed to the valve stem of the fuel cell, and an upper portion of the connector member may be adapted for a press fit on the valve stem of the metering valve. In this regard, the upper portion of the connector member may include a flexible wall having an inner diameter that is slightly less than the outer diameter of valve stem on the metering valve, to provide a frictional and/or interference-type hold on the metering valve stem, and a gap may be disposed radially outward from the flexible wall to provide a space for the displaced wall in the flexed condition. A fluid conduit is formed between the lower and upper portions so that a dispensable fluid may pass from the fuel cell, through the fuel cell valve stem and the metering valve stem, to a metering valve of the combustion gas-powered tool.  
         [0018]     A preferred embodiment of a fuel cell and connector of the invention is illustrated in  FIG. 1 . Fuel cell  10  includes an outer canister  12  having an elongated cylindrical tube  14  and a circular cover  16 . Tube  14  and cover  16  are generally made of a suitable metal material. The cover  16  is connected to tube  14  at a rolled seam  18  to form a gas-impermeable seam. As is known in the art, an inner bag (not shown), containing a dispensable fluid, may be disposed within the canister  12 . A pressurized propellant is stored within the canister  12  around the inner bag. When the fuel cell valve is open, the pressurized propellant collapses the inner bag and forces the fluid to be dispensed from the bag through a valve stem  20 . It is to be understood that the invention is not limited to this type of fluid dispensing canister. A unitary connector member  30  is secured at a dispensing end of a valve stem  20 . Connector member  30  may be made of soft plastic, a relatively inelastic plastic, or rubber, for example. Connector member  30  includes a conduit  32  for fluid flowing between the dispensing end of the valve stem  20  and a metering valve of a combustion gas-powered tool. A connector member of the invention may include structure for securing or coupling it to a metering valve, such as that which is formed at portion  34 , as described below.  
         [0019]     Referring to  FIGS. 2   a ,  2   b  and  2   c , connector member  30  generally includes a lower portion  36 , an upper portion  34 , and a fluid conduit  32  extending between lower portion  36  and upper portion  34 . As shown, connector  30  is symmetrical about axis A-A, but this is not a requirement of the invention. Lower portion  36  includes structure that may be engaged with the fuel cell valve stem  20 . Lower portion  36  includes a wall  37  having an outside surface  38 , an inside surface  42 , and a bottom surface  40  extending between outside surface  38  and inside surface  42 . The outside surface  38  is in the form of a conic section, while the inside surface  42  is in the form of a right cylinder. Other embodiments of the invention may employ shapes other than conic or cylindrical. Accordingly, these shapes employed for the connector should not be viewed as a limitation on the invention except as where specifically recited in the claim(s). Inside surface  42  defines a lower portion of fluid conduit  32 , and extends between bottom surface  40  to a flange  44  along the longitudinal axis A-A. Flange  44  extends radially inward from inside surface  42  and provides a stop for fuel cell valve stem  20 , as more fully described below. Conduct  32  may also be fit with soft, rubber-like seals or gaskets (not shown) at one or both of upper and lower portions  32 ,  34  for purposes of enhancing a fluid seal during operation.  
         [0020]     As noted earlier, upper portion  34  forms a connection to a metering valve stem on a combustion gas-powered tool. Upper portion  34  includes an outer wall  35   b , an inner wall  35   c,  and a base portion  35   a . Outer wall  35   b  includes an outside surface  46  and an inside surface  48 . Inner wall  35   c  includes an outside surface  50  and an inside surface  52 . Each surface  46 ,  48 ,  50  and  52  is in the form of a right cylinder. Inside surface  52  forms a right cylinder having a diameter d 1 . Surface  48  and surface  50  define a gap  54  which may be useful as a means for increasing flexibility of the wall  35   c  when receiving a slightly larger dimensioned stem of a metering valve. As such, inner wall  35   c  can be sized to flex when the metering valve stem of the combustion gas-powered tool is received in portion  34 , as described below. Thus, gap  54  maybe thought of as a flexure space for resilient inner wall  35   c . Inside surface  52  defines an upper portion of fluid conduit  32  and extends along the longitudinal axis A-A to flange  44 . Flange  44  also provides a stop for the metering valve stem. A material that yields (rather than an elastic material) upon insertion of the metering valve may alternatively be used. Such engagements may also be used for end  36 .  
         [0021]     In use, connector  30  is fixed to stem  20  by either an adhesive or heat shrink. Fuel cell  10  may then be packaged and delivered with a connector  30  secured thereto. Thus, in one embodiment of the invention, there is provided a fuel cell having a integral connector for connecting the fuel cell to a tool. In another embodiment, connector  30  may be delivered separately and then secured to the end of a fuel cell, such as the fuel cell disclosed in U.S. Pat. No. 5,115,944.  
         [0022]     As illustrated in  FIG. 3 , connector member  30  provides a fluid conduit between the valve stem  20  of the fuel cell  10  and a valve stem  56  of a metering valve  58  in a combustion gas-powered tool. In one embodiment, connector  30  is first inserted onto stem  20  before engaging connector  30  with stem  56 . Valve stem  20  is inserted into lower portion  36  of the connector member  30  so that an end  58  of the valve stem  20  abuts flange  44 . In another embodiment, connector  30  is already secured to stem  20  and the user may then simply connect connector  30  to stem  56 . Valve stem  20  may be adhered to inside wall  42  by an adhesive, to form an integral connection to the connection member  30 . In the illustrated embodiment, connector member  30  is sized for being received in fuel metering valve  58  such that stem  56  engages surface  52 . The valve stem  56  may be inserted into upper portion  34  so that an end  60  of the valve stem  56  abuts the flange  44 . Valve stem  56  has a diameter slightly larger than diameter d 1  of inside surface  52 , so that valve stem  56  may be press fit into upper portion  34  to form a frictional engagement with inside wall  52 . Alternatively, a circular ridge may be formed on surface  52  to form an interference fit between connector member  30  and stem  56 . The valve stem  56  may be made of a hard material such as metal, and the connector member  30  may be made of a flexible material such as plastic, so that when valve stem  56  is press fit into upper portion  34 , the inner wall  35   c  elastically flexes radially outward from axis A-A. Gap  54  provides a flexure space to allow inner wall  35   c  to flex radially outward.  
         [0023]     With the lower portion  36  of connector member  30  secured to the valve stem  20 , and the upper portion  34  of connector member  30  press fit on the valve stem  56 , a dispensable fluid may pass from the fuel cell  10  through valve stem  20 , fluid conduit  32 , and valve stem  56 , to the metering valve  58  of a combustion gas-powered tool.  
         [0024]     In a preferred embodiment, upper portion  34  is adapted to receive a protruding stem and as such, a female type fitting is formed. Additionally, outer walls  35   b  may be sized such that when connector  30  is to be connected to stem  56 , walls  35   b  assist with aligning conduit  32  with stem  56 .  
         [0025]     Although the foregoing description is directed to the preferred embodiments of the invention, it is noted that other variations and modifications will be apparent to those skilled in the art, and may be made without departing from the spirit or scope of the invention.