Abstract:
A protective shield fits onto a fuel cylinder that is mounted on a propane-powered or LNG-powered vehicle, with a cylindrical flange on the the tank surrounds a tank valve. The protective shield is formed of a cylindrical wall of a rubber-like material that fits snugly onto the cylindrical flange of the fuel tank, and has a window affixed into its upper end of the cylindrical wall. The window can be a disk of transparent Plexiglas. There are openings in the cylindrical wall to access the tank valve. The shield provides visibility of the tank valve but prevents any spray of the fuel that may escape from the tank valve from reaching the worker&#39;s face or other exposed skin.

Description:
[0001]    Applicant claims priority under 35 U.S.C. §119(e) of provisional patent application Ser. No. 61/645,699, filed May 11, 2013, the disclosure of which is incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    This invention concerns protective shields for industrial equipment, and in particular is concerned with a safety shield or cover that fits over the valves and fittings of a propane tank or other fuel gas tank as employed with powered industrial equipment, such as fork lifts, tractors, or the like. 
         [0003]    One continuing danger in respect to gas powered vehicles and devices is that the compressed gas can escape rapidly from the fittings during installation onto the fork lift or other vehicle, and can cause freezing of tissue to the worker if the spray contacts his or her face or exposed skin. Compressed gas stored in portable steel tanks is widely used in factory and warehouse environments nationwide, for powering indoor vehicles and other equipment. The danger from the escaping gas is a concern for worker safety Typically workers are required to wear goggles, safety glasses or face mask, as well as gloves, when installing or replacing a fuel tank, but these items do not provide complete protection for the worker. Under the current laws and guidelines, employers are required to provide a hazard-free environment for their employees. According to the Occupational Safety and Health Administration (OSHA), as stated in their OSHA Compliance Manual —, Personal Protection Equipment: the use of personal protection equipment or PPE, e.g., face shields, is considered a “last resort” or temporary type of protection. PPE itself can cause stress and create work hazards of its own, such as heat stress, impaired vision, and limits on mobility. For normal and ongoing operations, the first choice will always be given to elimination of the hazard in the environment, rather than relying on PPE. This doctrine is referred to as “implementing engineering controls”. 
         [0004]    To date, no engineering controls have been developed or proposed to address the problem of liquid fuel gas and compressed gas escaping and spraying onto workers when replacing an empty tank with a full one. This need has been addressed only using PPE, such as goggles or safety glasses and gloves or gauntlets. It would by far be preferable to stop any spray of this material before reaching the worker, and not to rely on the personal protection equipment. 
         [0005]    There is an unfulfilled need for a simple, comfortable, inexpensive, easy-to-install protective device for the tank itself, rather than relying on PPE fitted onto the worker. This would require a guard or shield that permits visual observation of the tank valve and fittings when installing or replacing the tank, and when opening or closing the tank valve, and which does not have to be worn by the worker. The solution to this problem would also require a shield or guard that can be easily slipped onto the tank over the tank valve, and can be easily removed from the tank so that it can be sent off for refilling or maintenance. The guard or shield should also be light weight and durable, without sharp edges that could cause cuts or other injury to the worker. 
       SUMMARY OF THE INVENTION 
       [0006]    This invention concerns a protective shield that fits onto the flange at one end of a tank or cylinder of compressed propane or butane as used in an industrial setting, i.e., for a forklift or similar warehouse vehicle. A cylindrical rubber wall or sleeve, or alternatively an extruded sleeve formed into a cylinder, has an inside diameter that fits snugly onto the cylindrical tank flange, and has access openings to allow the worker to attach the gas fittings and to open and close the tank valve. A circular clear window is placed into an upper end of the generally cylindrical wall, and allows clear visibility of the fittings and valve. At the same time, the window blocks any gas or liquid that escapes from the tank valve from exiting out the upper end of the shield, thereby protecting the worker from an accidental spray of the liquid propane or butane (which could cause freezing of tissues). This is intended to satisfy OSHA requirements for personal safety by blocking or eliminating the propane spray hazard before a face shield or protective eyewear and facewear is needed. 
         [0007]    Preferably, the cutouts or openings in the cylindrical shield wall include a generally rectangular wall aligned with the tank valve fitting, to allow the fuel hose to pass through, while the opening for the worker to reach through to turn the valve can be formed of crossed slots, i.e., shaped like the letter “X”. This minimizes the open area of the opening when the worker is operating the valve, which will limit the possibility of escaped fuel gas exiting through the reach-in opening. The X-shaped opening can also serve to retain the glove or gauntlet between uses, so the worker has easy access to the safety gloves. 
         [0008]    In a preferred embodiment, the cylindrical wall of the shield is formed of an extrusion of a rubber or synthetic elastomeric resin, with ends butt welded to form a ring. A reinforcing ring is formed on an outer surface of the wall at its lower end, and at the upper end there may be a band of a distinctively colored material, e.g., bright orange or bright green, to increase the visibility of the shield. At the upper end of the cylindrical wall, at the inside surface, an inwardly directed flange locates the clear plastic disk or other window that held in place here. Other possible constructions of the shield wall are also possible. 
         [0009]    The material of the wall may have a weakly conductive filler so that static electrical charge will dissipate, and not pose a threat of static discharge. 
         [0010]    In a preferred implementation, the rubber cylindrical wall is about seven inches high, with a twelve-inch inside diameter, and with a clear Plexiglas disk serving as the window. In some possible embodiments, the window may be partly transparent and partly opaque or translucent. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0011]      FIG. 1  and  FIG. 2  are perspective views of a typical propane fuel tank and a protective shield according to an embodiment of this invention, with  FIG. 2  showing a worker installing the protective shield onto the flange of the tank. 
           [0012]      FIG. 3  is a top plan view of the protective shield installed onto the flange of the tank. 
           [0013]      FIG. 4  is a side view of the protective shield of this embodiment installed on a tank. 
           [0014]      FIG. 5  is a perspective view showing the tank with protective shield being placed onto the tank cradle of a vehicle. 
           [0015]      FIG. 6  is a perspective view showing the tank with protective shield as having been installed on the tank cradle of the vehicle. 
           [0016]      FIG. 7  is a perspective view thereof showing a worker attaching a vehicle fuel line to the tank valve. 
           [0017]      FIG. 8  is a perspective view thereof showing the worker opening the tank valve 
           [0018]      FIG. 9  is a layout diagram of the rubber wall portion that forms the cylindrical wall of the protective shield, showing the valve access openings and a position pin opening. 
           [0019]      FIG. 10  is a side cross section thereof showing a recess for fitting the clear disk window portion thereof. 
           [0020]      FIG. 11  is a plan view of the clear disk window thereof. 
           [0021]      FIG. 12  is a side elevation of the cylindrical wall portion showing the general height and diameter thereof. 
           [0022]      FIG. 13  is cross section of the cylindrical wall portion according to an alternative embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]      FIG. 1  shows a typical propane tank  10  as used as a fuel source for a warehouse vehicle. The tank  10  holds a quantity of compressed and liquified fuel such as propane. The tank  10  is made of steel and has a generally cylindrical steel flange  12  at its upper end, approximately twelve inches in diameter, with various fittings and connections within the flange  12  including a tank valve  14  that connects to the fuel hose for the vehicle. A protective shield  20  according to an embodiment of this invention is shown here next to the tank  10 , and generally takes the form of a cylindrical cap or cover to fit onto the cylinder flange  12 . The protective shield has a sturdy, flexible rubber wall  22  in the form of a cylinder having an inner diameter of approximately twelve inches and a height of about seven inches, with a first valve access opening  24 , a key slot  26 , and a second valve access opening  28  cut into it. A transparent plastic window  30  is mounted at the upper end. The window here is in the form of a clear Plexiglas disk having a diameter of about twelve-and-one-quarter inches and a thickness of about ⅜ inch to ⅝ inch, preferably one-quarter inch.  FIG. 2  shows a worker W mounting the shield  20  onto the flange  12  of the tank  10 , with the openings  24 ,  26 ,  28  aligning with corresponding openings on the tank flange  12 . 
         [0024]    As shown in  FIG. 3 , once the protective shield  20  is installed onto the flange  12 , the window  30  covers the entire extent of the upper end of the flange  12 , but the tank valve  14  is visible through the window.  FIG. 4  shows the fitting of the tank valve  14  being accessible for attaching the fuel hose through the valve access opening  24  in the shield wall  22 . In alternative embodiments, some portions of the disk could be opaque. 
         [0025]    As shown in  FIG. 5 , the worker W is installing a full fuel tank  10 , with the shield  20  in place on the flange  12 , onto a forklift of similar vehicle  34  by laying the tank  10  horizontally on a tank cradle  32  of the vehicle  34 , with the flange  12 , valve  14  and shield  20  at the right hand side of the vehicle, so that the tank  10  is positioned as shown in  FIG. 6 . The worker W then attaches a fuel hose  36 , feeding it through the access opening  24  and attaching it to the tank valve  14  by rotating or screwing on a threaded fitting  38 . For purposes of illustration, the worker W&#39;s hands are shown, but in practice the worker W would wear protective gloves for this operation. Then, as shown in  FIG. 8 , the worker W can reach in through the X-shaped valve access opening  28  with his gloved hand to rotate the tank valve  14  to open it. During this entire operation, the window  30  of the protective shield stands between the valve  14  and the worker, except for his gloved hands. The worker W sees the valve  14  clearly during installation of the fuel hose fitting and when the worker opens the valve, but the window  30  will protect the worker from any spray of the compressed liquid fuel that might escape during this operation. 
         [0026]    The protective shield  20  remains in place during operation of the vehicle  34 , and when the empty tank  10  is removed, the shield can be slipped off and placed on the tank flange  12  of a fresh fuel tank. 
         [0027]      FIGS. 9 and 10  show some of the structure of the body of the cylindrical rubber wall  22 , here a blank  32  that is laid flat, and which can be wrapped into a cylindrical shape and the ends fastened or adhered together. The ends are preferably joined as a butt weld  33  (see also  FIGS. 1 and 3 ). The rubber-like material of blank  32  may have a filler of carbon or another weakly conductive material so as to dissipate any static charge that may be imposed on the shield from handling, to minimize risk from static discharge. The blank  32  has a height of about seven inches and a length of about three feet, four inches. The valve access openings  24  and  28  are cut out to have, in effect, a height dimension of three inches and a length dimension of six inches, and the key slot opening  26  has a height dimension of two-and-three-quarters inches with a length dimension of one-half inch. As shown in cross-section of  FIG. 10 , near its upper edge, the cylindrical wall  22  has an inwardly directed solid lip or flange  34  that is situated at an upper edge of the wall, i.e., the top edge of the blank  32 . This lip  34  defines surface or location  40  that the disk  30  seats against. The outer side of the upper edge of the cylindrical wall  22  is curved or chamferred, and a band  36  of a highly visible distinctive color, e.g., yellow or orange, is affixed here. This color band  36  makes the presence of the shield  20  more visible under warehouse lighting conditions. At a lower edge of the cylindrical wall  22 , a reinforcing ring  38  is present, preferably formed as a lower part of the blank  32 . 
         [0028]    A plan view of the window disk  30  is presented in  FIG. 11 , and a side elevation of the shield or guard  20  is presented in  FIG. 12 . 
         [0029]    In an alternative construction, as presented in  FIG. 13 , the rubber wall  122  can be of about half-inch to five-eighths inch thick rubber or rubber foam material, with a continuous elongated cutout  140  of about one-quarter inch depth for capturing the edge of the window disk  30 . 
         [0030]    The clear plastic window disk  30  ( FIG. 11 ) of this embodiment has a diameter of about twelve-and-one-quarter inches, with a thickness of one-quarter inch. The disk can be entirely clear, or may have some portions that are translucent or opaque, and may include reinforcement, as needed. 
         [0031]      FIG. 12  shows the shield or guard in an elevation profile, and the shield wall  22  has a height of seven inches and a diameter of about thirteen inches. The shield should be dimensioned to fit the end flange of a given type of tank. 
         [0032]    Many alternative arrangements of the tank shield of this invention can be constructed without departure from the main principles of the invention. The cutouts or openings  24  and  28  may be reversed from what is shown here, depending upon the orientation of the associated tank valve. The tank guard should be constructed to be light-weight and durable, and the materials from which it is constructed may thus may be selected from many possible materials 
         [0033]    In alternative embodiment, the cylindrical wall may ends joined by blind byrd insert fasteners, and other alternative fastening systems could be employed. In other possible embodiments, the wall  22  may be formed of a generally cylindrical extrusion of a suitable flexible durable material. Also there are other ways in which the window  30  can be attached or affixed into the upper end of the cylindrical wall  22 , and in some possible embodiments the window  30  need not be of a circular shape. As an alternative to the more-or less solid wall  22  with only the three access opening  24 ,  26 ,  28 , the protective shield may be made with upper and lower rings joined by a series of axial ribs, leaving most of the cylinder flange  12  uncovered except the protective window. In that case, the ribs may be of a more rigid material, at least in part. 
         [0034]    While the device of this invention has been explained and illustrated with respect to a preferred embodiment, it should be understood that many other possible embodiments would be apparent from this disclosure to persons skilled in the art, without departure from the scope and main principles of the invention.