Abstract:
The invention relates to a gravity filling system for adding water to wet cell batteries. The system is for one or more batteries and incorporates a new and improved cell plug which will reduce risk of hazardous gases and toxic acids to the operator. The cell plug incorporates a styrofoam packed float chamber, that forces a float needle to seal off the cell when the water level reaches a predetermined desirable level. The device fills the battery level without overfilling which can be as detrimental as not filling it enough. The operator can by visual inspection ascertain when the filling of any particular battery has been completed.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is based on Provisional Patent Application Ser. No. 60/095,332 filed on Aug. 4, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to the safe refilling of battery cells to a predetermined level. More particularly, the present invention pertains to a new and improved battery electrolyte cell plug which automatically controls the liquid level in the battery cell. 
     2. Description of the Prior Art 
     There is an inherent danger in refilling the electrolyte levels of wet cell batteries. For instance, the batteries of an electric golf cart need to be recharged after a designated period of use. Most course maintenance programs charge the batteries every day if the golf cart was used for 18 holes. This constant charging and discharging will result in loss of electrolyte due to evaporation. If the level of electrolyte in a given battery cell drops below the tops of the electrode plates, irreparable damage to the plates can occur. Also there is an increased corrosion of active material which leads to the detriment of cell life and quite often there is an increased risk of arcing between exposed, and possibly faulty plates, which could ignite any inflamable gases present. High temperatures in the cells will also cause expansion of the electrolyte. It is thereby important, to not only allow for expansion of the electrolyte in the cells by venting and dispensing of explosive gas mixtures, but also to periodically add electrolyte to the cells to compensate for the inherent losses. 
     Care must be also be exercised in order not to overfill the cells. If the intended liquid level is exceeded, this represents a reduction of the gasing space in the battery interior above the liquid level. This space is required for the collection of the gas/electrolyte mixture that forms during the operation and especially the charging of the battery. An overfilled cell may prevent oxygen and hydrogen, which are generated within the battery, from safely escaping into the atmosphere. A build up of these gases may buckle the plates and possibly lead to an explosive condition. 
     Maintenance personnel at golf courses are often relatively inexperienced. It is common for golf courses to hire teenagers for a summer job. Safety therefore is of paramount importance. The first step in refilling a battery is to remove the plugs, which in the case of a golf cart having six batteries would total 18 cell plugs. While refilling there is the danger of accidental splashing of sulfuric acid electrolyte on clothes, skin or eyes. The present invention seeks to provide a system whereby the danger to personnel is minimized, if not entirely eliminated, and the refilling operation reduced to a fraction of the time presently necessary. A very important factor when some golf courses have upwards of 60 to 80 golf carts. 
     U.S. Pat. No. 3,434,887 issued to A. E. Seckinger on Mar. 25, 1969, teaches the use of an apparatus to refill golf cart batteries. Seckinger shows the use of an automatic refill system that utilizes a pump to generate water flow. This system requires outside power to refill the cells. 
     U.S. Pat. No. 5,284,176 issued to Daniel Campau on Feb. 8, 1994, discloses a system for refilling a series of interconnected battery cells to a predetermined level by using individual refill valves, each associated with a single cell. A single supply reservoir is taught. Campau directs his teachings more to the composition of the supply tubing. 
     U.S. Pat. No. 4,749,633 issued to Leonard W. Elias on Jun. 7, 1988, shows a device that is mounted in the battery cell opening which receives the water. He utilizes a float that causes a valve pin to rise or fall in response to the liquid level in the cell. 
     U.S. Pat. No. 5,002,100 issued to Patrick Frederick on Mar. 26, 1991, discloses a gravity feed water reservoir which feeds water to a plurality of cell openings. Frederick discloses a valve member extending into each cell but not as a cell cap. 
     U.S. Pat. No. 4,522,896 issued to Barry S. Iseard on Jun. 11, 1985, teaches of an automatic watering system and the use of cell caps, adapted for retrofitting an existing battery. 
     U.S. Pat. No. 4,007,764 issued to Royal F. Bandemor on Feb. 15, 1977 is an automatic fluid filling device wherein the device itself consists of a plurality of members, each removably insertable into a battery cell. The cells are connected in series with the reservoir at one end of the series. This system requires a pump for recirculation. 
     U.S. Pat. No. 4,386,141 issued to Evert C. Weidner et al. on May 31, 1983, teaches a battery watering refill device for maintaining a predetermined electolyte level in each cell of a battery. 
     U.S. Pat. No. 4,219,612 issued to Edwin Tatlock on Aug. 26, 1980, teaches the use of a vent plug to allow the potential explosive mixture of gases to vent through the safety of a flame trap. 
     U.S. Pat. No. 4,113,925 issued to Werner Kohler et al. on Sep. 12, 1978, teaches the need to address the dangers of over filling an electrolyte cell and hazardous gas/electrolyte mixture that forms during the charging of the battery. 
     The concepts of the present invention are suggested for a host of possible applicatons. Electrically powered golf carts are discussed, but many other possible applications are readily seen. One large application area would be in material handling equipment where the handling unit comprises the use of multiple packs of batteries. Therefore, it will be appreciated that the invention can be utilized by any equipment that is battery powered and the batteries are intended to be periodically recharged. 
     None of the above inventions, taken either singularly or in combination, are seen to describe the instant invention as claimed. 
     SUMMARY OF THE INVENTION 
     The present invention relates to an improved battery cell plug for permitting wet-cell batteries to be safely refilled, whether it be a single battery or multiple battery packs. The present invention does not require any outside power to circulate the refilling water, but can rely solely on gravity to feed the water into each electrolyte cell. However, the design concepts of the present invention battery plug would be equally effective regardless of the means for supplying water. The instant invention seeks to provide a refilling system that diminishes the risk of toxic and explosive gas hazards. 
     The new and improved cell plugs will replace the original battery plugs. In most circumstances this would consist of three cell plugs per battery. An application example would be a golf cart, the majority of carts employing six batteries for a total of 18 cell plugs per cart. 
     The instant invention will allow for the simultaneous filling of a single battery of a group of batteries with the same effortless ease. Each cell plug allows the cell to fill and individually shutoff at the the proper level. The cells do not require a sight gauge but rather only a visual sighting of water overflowing when the batteries are full. The water supply means will simply be closed when the procedure is complete. The new cell plug fits into the battery exactly as did the original equipment plug. Installation of the present invention does not require changes to be made to any battery arrangements, since all parts are snap-fitted into place. 
     Accordingly, it is a principal object of the invention to provide a refill system with a cell cap plug which will indicate to the operator when to shut off the flow of water upon the cell being filled to its required level. 
     It is another object of the invention to provide a cell cap that will not allow any acid/electrolyte to escape which causes weakening of the battery and also environmental damage. 
     It is a further object of the invention to provide a chamber float in the overflow cap which will prohibit any unwanted venting, thereby restricting the venting to the passive area vent hole of the cell cap. 
     It is yet another object of the invention to provide a system which does not require an external power source, but uses gravity to force the liquid through the system. 
     It is an object of the invention to provide a safe refill system whereby any possible sulfuric acid accumulation will not come into contact with the operator&#39;s skin, eyes or clothing. 
     It is also an object of the invention to provide a system that can be operated by a person with a marginal level of mechanical skills. 
     It is an object of the invention to provide a system whereby the entire process is self contained with only the addition of water being required of the operator, possibly from a reservoir tank. 
     It is another object of the invention to have all parts interchangeable with the original battery parts. 
     It is yet another object of the invention to have an inexpensive system with virtually all parts manufactured out of plastic or rubber material. 
     It as a further object of the invention to provide a filling system which minimizes the risk of being splashed by acid or having a spark ignite the hydrogen gas that is often lurking about. All pieces and parts are acid resistant and of a non-arc producing material. 
     These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevated view of the basic cell plug. 
     FIG. 2 is an elevated view of the S-cell plug which has a minor design alteration allowing it to be used in a series relationship with other batteries. 
     FIG. 3 is an elevated view of the basic cell plug with an overflow arrangement in the cell cap. 
     FIG. 4 is a cross-sectional view of the basic cell plug. 
     FIG. 5 is a cross-sectional view of the overflow cell cap. 
     FIG. 6 is pictorial cut-a-way view of the float chamber housing. 
     FIG. 7 is an expanded elevational view of the float container being symetrical from all sides. 
     FIG. 8 is an elevational view of the float needle. 
     FIG. 8 a  is a bottom view of FIG.  8 . 
     FIG. 8 b  is a top view of FIG.  8 . 
     FIG. 9 is an elevation view of the needle housing tube being symetrical from all sides and the vent chamber disc molded into the tube. 
     FIG. 9 a  is a top view of the vent chamber disc and needle housing tube. 
     FIG. 10 is a perspective view of the vent chamber barrier. 
     FIG. 11 is an elevational cross-sectional of the seat seal. 
     FIG. 11 a  is a top plan view of the seat seal of FIG.  11 . 
     FIG. 12 is an elevational side view of the cell plug with the transition unit seated therein. 
     FIG. 12 a  is a bottom view of FIG.  12 . 
     FIG. 13 is a front elevational view of the filling of a single battery with two of the S-cell plugs of FIG.  2  and one with an overflow float chamber of FIG.  3 . 
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention provides for a battery cell plug for permitting a wet-cell battery to be safely refilled with water. The repeated recharging of these batteries causes the dissipation of water in the electrolyte, thereby creating the need for the present invention. The new and improved battery cell plugs virtually eliminate the hazards of accidental splashing of sulfuric acid, and will also indicate to the operator when the refilling procedure is completed. The present invention will require little or no change to conventional battery structure. A major application area for the instant invention can be found in electrical golf carts where upwards of six batteries are normally employed. Other areas are with such high voltage and high powered battery applications such as in material handling equipment and electrical personnel carriers, especially those designed for the handicapped. 
     A basic cell plug is generally depicted by the reference numeral  20  in the accompanying FIGS. 1 and 4. This cell plug will be described in more detail further on in the disclosure. FIG. 2 shows an S-cell plug  21  which has been modified from the basic cell plug  20  by the addition of an water exit line  85  to enable it to be used in series with other cell plugs. FIGS. 3 and 5 depict an overflow cell plug  22  which is merely the basic cell plug  20  modified to allow for refill water to overflow the plug when the battery reaches the proper level. 
     As was previously discussed, the electrolyte level of a wet cell battery must be maintained in a relatively narrow range. The operation of the cell plug is critical to the entire procedure. Basic cell plug  20  has a foundation comprising of a float chamber housing  30  as shown in FIG.  6 . Float chamber housing  30  is hollow and generally cylindrical with openings at the top  31  and the bottom  32 . The bottom portion being insertable into the battery cell hole vacated by the original equipment cell plug. An inner annular wall  33  forms an inner chamber  34 . The upper wall surface having defined therein a pair of oval shaped vent openings  35  near upper edge of wall. Inner wall  33  is fluted to reduce capillary, static and friction forces. Upper inner wall surface  33  having a preformed groove  36  defined distal-proximate therein. Slidably deposed and vertically movable in chamber housing  30  is a hollow concentric float container  37  as shown in FIG.  7 . It is comprised of two sections, a concentric lower disc  38  and a concentric upper float section  39 ; the two sections having conventional connecting means for being snapped together. Styrofoam packing  40 , having a general shape like the interior of float container  37  is placed within float container  37 . An upper surface  41  of upper float section  39  being domed shaped to prevent water residue thereon and having a circular aperture  42  in the center thereof. Lower disc section  38  is also domed on the bottom to prevent air bubble entrapment. It is understood that float container  37  could also be “blow molded” and filled by injection with styrofoam. Styrofoam packing  40  prevents condensation from forming, which could add weight and upset the filling levels of the cells. 
     FIG. 8 depicts an elongated float needle  43  having a slotted needle bottom  44  for extending through the circular aperture  42  of float container  37  thereby forming a friction tight connection between the two bodies. Needle  43  having a longitudinally central axis stem  45  extending the length of needle  43 . Needle  43  further having three equidistant fin-like projections  46  extending upwardly the length of stem  45 . Float needle  43  having a concentric bullet shaped rubberized tip  47  at its upper portion. A rubberized hollow conically shaped nose cone  48 , having an interior cavity  49 , generally the shape of tip  47 , having an opening  50 , and having means for fitting tightly in a friction fit over tip  47 . Nose cone  48  having an air space  51  to afford it a flexibly cushioned seal. FIG. 8 a  is a bottom view of needle  43  while FIG. 8 b  depicts a top plan view. 
     Extending coaxially about float needle  43  is a concentrical elongated hollow needle housing tube  52  as shown in more detail in FIGS. 9 and 9 a  for accurately guiding float needle  43 . Needle housing tube  52  having a vent chamber disc  53  molded integrally to it. Housing tube  52  having a shoulder  56  encirculating the outer surface near the upper part of tube  57 . Vent chamber disc  53  is integrally molded to needle housing tube  52 , with disc  53  extending within the bottom section of tube  52 . Vent chamber disc  53  having a flange  59  defining vent guide ribs  60  which interact with a vent chamber barrier  61 , as depicted by FIG.  10 , to form a vent chamber  62 . Chamber barrier  61  is longitudinally coextensive with vent chamber guide ribs  60  of disc  53 , barrier  61  having a concave surface  63  centerward, and an indented end  65  outwardly meshing with vent guide ribs  60 . 
     A molded rubber needle seat seal  66 , concentric in shape, is depicted by FIGS. 11 and 11 a  wherein seat seal  66  is received into needle housing tube  52  by having seat seal  66  fitted into a lower opening  54  of tube  52 . A tapered opening  67  of seat seal  66  is pushed upwardly against an abutment  58 , which is located in the inner midpoint section of tube  52 . Seat seal  66  having a tapered inner wall  68  and is molded to give greater flexibility when mated to float needle nose cone  48 , which guarantees the shut off of water flow when each cell is filled to its desired level. A seal locating ferrule  70 , being a concentric hollow cylinder, is pressed fit under a bottom orifice  69  of seat seal  66 , flush with disc flange  59  of needle housing tube  52 , whereby minor pressure is exerted on the outer diameter of needle seat seal  66  to prevent any by-pass of liquid once the battery cell is shut off by the normal action of float needle nose cone  48  and tapered opening  67  of seat seal  66 . 
     FIGS. 12 and 12 a  show a cell cap  71  with a cell vent hole  75 , a bottom cell entry  74 , and a top cell cap opening  73 . Defined within the interior surface of cell cap  71  is a passageway  72 . Molded into thse underside of cell cap  71  is a hollow concentrical transition unit  76  having a pair of vent slots  77  located on the bottom portion and an O-ring projection  78  encircling about the center section of unit  76 . Transition unit  76  forming a bond between float chamber housing  30  and the rest of the structure. The O-ring projection  78  in a tight friction fit with preformed groove  36  of inner annular wall  33  of housing  30 . The vent slots  77  are in alignment with the oval vent openings  35  of chamber housing  30 . A rubber gasket seal  79  seals cell cap  71  to the battery cell. Housing tube  52  and vent chamber disc  53  are kept in the proper orientation with transition unit  76  by a key  64  as shown in FIG. 12 a . Cell cap  71  accepts needle housing tube  52 , seat seal  66  and locating ferrule  70  in passageway  72  of cell cap  71  which is positioned flush with the shoulder  56  of tube  52 . The upper end of housing tube  52  defining an upper opening  55  protruding upwardly through cell cap  71 . A plurality of protruding rings  57  deposed in close proximity to upper opening  55 . 
     A generally hollow fill inlet cover  80  having a chamber  82  within with an open bottom  84 . A plurality of circular channels  83  are defined within chamber  82  in close proximity to opening  84 . The cover  80  is pressed down over the raised protruding rings  57  of the tube  52  to form a friction pressure fit with channels  83 . A water fill inlet  81 , which is connected to a water source  23 , completes basic cell plug  20 . 
     A modification to basic cell plug  20  is a water exit line  85  which forms the S-cell plug  21  shown in FIG.  2 . This enables the plug to be used in series with other plugs. 
     FIGS. 3 and 5 disclose another modification of the basic cell plug  20 , an overflow cell plug  22 , whereby an overflow fill cover  86  has contained therein an overflow float chamber  87 . Float chamber  87  having a lid opening  95  in its top section. An overflow float  88 , having a conically tapered end  89  on the bottom portion, is deposed within the chamber  87  juxtaposed above a float valve section  90 . Whenever the electrolyte level of the battery cell in which cell plug  22  is employed, is in an unsated state, tapered end  89  will depose within a conical seat portion  91  of valve section  90  to form a water seal which will prevent water from exiting the plug at that time. This closing also prevents any venting of gases, forcing all ventilation through the passive area of the cell cap vent hole  75 . Upon reaching a fill condition, float  88  is pushed upwardly, thereby opening valve section  90  to allow water to exit through an overflow line  94 . The cell cover  86  is placed on housing tube  52  in the same manner as the other plugs  20  and  21 . Cell cover  86  does incorporate a chamber lid  92  which uses an O-ring type gasket  93  to engage top opening  95  of float chamber  87 . 
     Only water is allowed to escape because the specific gravity of the electrolyte will keep it below the specific gravity of the water. It is very important that no acid or electrolyte escape which can not only weaken the battery, but can also cause serious environmental damage. The added water mixes into the cell system during charging and the mixing process is also aided when the batteries are in motion (such as when a golf cart moves). 
     FIG. 13 shows a single battery  25  being refilled with three cell plugs in series. This particular configuration uses two S-cell plugs  21  and an overflow cell plug  22 . Conventional means  24  are used for conveying water from one cell to another. Many differednt configurations are possible depending on the nember and arrangement of the batteries. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.