Abstract:
The specification discloses a wet vacuum/extractor including an add-on liquid dispensing system. A liquid supply tank removably mounts on the vacuum and couples with the vacuum exhaust for momentarily pressurizing the tank to prime the liquid dispensing system. A remote pump is included at the wand handle and is powered by low voltage current from the vacuum.

Description:
This is a continuation of application Ser. No. 07/580,809, filed Sep. 11, 1990, and now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to surface cleaning extractors and wet vacuums. Such extractors are devices which apply a cleaning solution to a surface, such as carpet, upholstery and the like, and then vacuum the solution from the surface, extracting dirt and debris from the surface. Such extractors sometimes use built-in solution tanks and sometimes include attachment means with a long hose so the unit can obtain water from a faucet. 
     When a built-in solution tank is used, some means for pumping the solution from the tank to a cleaning tool is required. Such pumping function is typically accomplished by an electric pump which draws the solution from the tank and delivers it to the cleaning tool. Often times such pumps are expensive, self-priming units. Alternatively, such pumps can be non-self-priming and positioned such that gravity feeds the solution from the tank, to the pump for priming purposes. The pumping function can also be accomplished by pressurizing the solution tank and forcing, rather than drawing, the solution from the tank. 
     Both approaches are taught by Hurwitz in U.S. Pat. No. 4,123,818. Hurwitz discloses a closed pressure vessel or reservoir 10 which is pressurized via an air pump 28 for forcing the solution from the reservoir. Alternatively, a liquid pump assembly 128 is provided to drawn the solution from the tank. Inconsistent delivery of solution results from the use of the air pressurizing pump because the pressure within the reservoir decreases as solution leaves the reservoir. Further, subsequent pumping is required to repressurize the reservoir. Alternatively, the use of a liquid pump assembly adds cost and weight to the apparatus. 
     The various British and U.S. patents to Brazier (British Patents 2,038,168; 1,602,919: 1,602,918 and 1,601,456 and U.S. Pat. Nos. 4,287,636: 4,218,805 and 4,185,354) disclose a floor cleaning system in which the cleaning solution tank is pressurized by the extractor&#39;s suction fan exhaust. However, the pressure developed in the solution tank is back pressure to the suction fan and decreases the effective suction of the fan. Alternatively, a larger capacity suction fan assembly is required for a given level of suction when the exhaust is used to pressurize a solution tank for delivering solution to a cleaning tool. This results in a larger, more expensive and heavier suction fan assembly. 
     The commonly known home shop vacuum is typical of a wet vacuum. Such vacuums have the capability to vacuum liquid from a surface, but were not originally designed with a cleaning solution dispensing function. Accessory kits to add the cleaning solution dispensing function to wet vacuums are now becoming popular. A small solution tank is mounted on the cleaning wand and cleaning solution is drawn by gravity from the tank to the cleaning head for dispensing. Such a system has limitations. The cleaning solution tank is inherently small and limited in capacity, in turn limiting the size of the surface which can be cleaned for each filling of the cleaning solution tank and requiring frequent refillings to clean a room sized area. Also, the solution tank adds weight to the wand and diminishes its maneuverability. 
     SUMMARY OF THE INVENTION 
     Such deficiencies and problems are resolved by the present invention wherein a cleaning solution tank is mounted on the vacuum housing, rather than on the cleaning tool, and is connected to the vacuum exhaust so that the exhaust can be used to temporarily pressurize the solution tank for priming the solution delivery system. However, the exhaust is not used to continuously pressurize the solution tank. Thus, back pressure is not created against the suction blower and the vacuum suction effectiveness is not compromised during use. This arrangement allows the use of a generous solution tank to minimize the need for solution refilling. The inherent bulk and limitations of a faucet connected system are avoided. Further, the cleaning tool is not encumbered with the weight and bulk of a cleaning solution tank which has an inherently inadequate capacity. While the invention is especially advantageous when used as an &#34;add-on&#34; tank for a wet vacuum, it is applicable in its broader aspects to fixed solution tank extractors. 
     In one aspect of the invention, a small pump is located in the tool handle for enhancing and controlling the flow of cleaning solution. In another aspect of the invention, an A/C step-down transformer is provided with a D/C rectifier in the wet vacuum to minimize any chance of a shock hazard by using a low voltage power supply to the pump and to realize the cost advantage of a D/C powered pump. 
     These and other objects, advantages and features of the present invention will become apparent upon review of the following specification in conjunction with the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view showing the solution tank and wand handle of the invention mounted on a wet vacuum; 
     FIG. 2 is a section view at section plane II--II of FIG. 1, showing the solution tank of the invention and showing in phantom the profile of the top of the wet vacuum of FIG. 1; 
     FIG. 3 is a detail of the exhaust valve of the solution tank with the valve in the open position; 
     FIG. 4 is a perspective view of the solution tank elevated above the vacuum of FIG. 1; 
     FIG. 5 is a plan view of the solution tank bottom; 
     FIG. 6 is a detail of the exhaust valve of the solution tank with the valve in the closed position; 
     FIG. 7 is a side elevation of the wand handle of the invention; 
     FIG. 8 is the view shown in FIG. 7 with a side cover removed to show the inside of the wand handle; 
     FIG. 9 is the section view of FIG. 2 showing an alternative embodiment of the exhaust valve arrangement; 
     FIG. 10 is a detail of the exhaustive valve of FIG. 9 in the open position; and 
     FIG. 11 is a detail of the exhaust valve of FIG. 9 in the closed position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the preferred embodiment, a cleaning solution tank 20 and cleaning tool handle 60 of the present invention are shown in conjunction with a wet vacuum 100 (FIG. 1). The vacuum 100 includes a recovery tank 102, a suction hose 104, a cleaning tool 106 and a housing 108. A conventional vacuum fan is located within the housing 108 which also has a vacuum fan exhaust outlet 110. 
     Tank 20 is seated atop vacuum 100. Tank 20 has a top 22 and a bottom 24 which is configured to couple with housing 108 of vacuum 100 (FIG. 2). Tank 20 is preferably molded of a polystyrene plastic with a notch formed in the back of tank 20 to provide access to power switch 112 of vacuum 100. Handles 21 for ease of removing and carrying tank 20 are provided on each side of tank 20. An exhaust tube 26 is secured to and projects below bottom 24 of tank 20 for coupling with exhaust outlet 110. Exhaust tube 26 also extends upward through tank 20 into an opening in tank top 22 which is defined by an exhaust collar 28. Exhaust collar 28 is secured to top 22 and is concentrically positioned around and spaced from exhaust tube 26 to form an annular air passage 30. 
     A pressure cap 32 is positioned over collar 28 and has a stem 34 projecting downwardly from cap 32 to slidably connect cap 32 with exhaust tube 26 (FIGS. 2 and 3). A stem sleeve 36 is generally centered inside the upper end of exhaust tube 26 for receiving stem 34. Sleeve 36 is attached to tube 26 by three sleeve supports 38. Stem sleeve 36 has a generally centered vertical aperture 40 for slidably receiving ca stem 34 such that the sleeve and stem locate pressure cap 32 in sealing contact with exhaust collar 28 when a downward force is applied to cap 32. Cap stem 34 and stem sleeve 36 also cooperatively engage so that pressure cap 32 cannot be lifted more than a short distance above exhaust collar 28 as shown in FIG. 3. 
     In the broader aspects of the invention, solution tank 20 can be pressurized with the vacuum exhaust stream merely by covering exhaust collar 28 with the palm of an operator&#39;s hand or by the use of a pressure cap 32 which is simply tethered to remain in the vicinity of exhaust collar 28. However, the most preferred structure described above, enhances the performance of the invention by dampening exhaust noise and providing convenience of operation. 
     Tank 2 is filled with cleaning solution through a fill tube 44, provided in top 22 of tank 20 (FIG. 2). A fill cap 46 positions and secures a solution suction hose 48 which penetrates cap 46 and extends at one end to bottom 24 of tank 20. 
     The other end of suction hose 48 extends to cleaning tool handle 60 where a connector 62 connects hose 48 to a pump assembly 64, housed in handle compartment 66 (FIGS. 7 and 8). Solution which is drawn through suction hose 48 is pumped through a solution feed line 68 to a valve 70 and a dispensing line 72 for dispensing solution independently to a surface. Valve 70 is actuated by a trigger 74 and controls the flow of cleaning solution. 
     Pump 64 is preferably a low voltage, direct current (D/C), centrifugal pump. Power is supplied for pump 64 through a power cord 76 which is connected by a connector 78 at one end to the low voltage side of an alternating current (A/C) step down transformer, contained within housing 108 (FIG. 4). A low voltage D/C rectifier 79 (FIG. 8) is preferably provided at the low voltage side of the transformer to provide a low voltage D/C current for pump 64. The high voltage side of the A/C step down transformer is supplied with household current through the conventional power cord and power switch of wet vacuum 100. The other end of power cord 76 passes through a strain relief 80 and connects to a power switch 82, in handle compartment 66 (FIG. 8). Thus, high voltage remains contained within housing 108 of wet vacuum 100 and only low voltage, less than 35 volts and preferably about 9 volts, is transmitted outside vacuum 100 to pump 64. Further, the performance advantage of using a D/C powered pump 64 is realized by including a D/C rectifier to convert the A/C current to D/C current. 
     In use, a cleaning solution will typically be mixed in tank 20 by pouring a cleaning solution concentrate into tank 20, through fill tube 44, and then conveniently filling tank 20 with water from a faucet. Tank 20 is easily carried to and placed upon vacuum 100, aligning and inserting the lower end of exhaust tube 26 into exhaust outlet 110 (FIG. 4). Fill cap 46, with suction hose 48 depending therefrom, is fitted to fill tube 44. To commence cleaning, the solution distribution system is primed by turning on vacuum 100 and covering exhaust collar 28 with pressure cap 32 by pressing upon the top of cap 32 with the operator&#39;s hand to seat cap 32 down in sealing contact with collar 28 as shown in FIG. 6. As indicated by the arrows in FIG. 6, the exhaust stream from vacuum 100 travels upwardly through exhaust tube 26 toward pressure cap 32 which deflects the exhaust stream through the annular passage 30 and inside tank 20 to pressurize the tank. As an operator uses one hand to pressurize tank 20 by depressing pressure cap 32 into sealing contact with exhaust collar 28, trigger 74 is actuated by use of the operator&#39;s other hand to open valve 70 and allow the pressure developed in tank 20 to force cleaning solution through suction hose 48, pump 64, feed line 68, valve 70 and dispensing line 72, thus priming the solution dispensing system (FIGS. 7 and 8). Once the solution dispensing system is primed, pressure cap 32 is released and the vacuum exhaust stream lifts cap 32 to an open position as shown in FIG. 3 so that the exhaust stream travels up through exhaust tube 26 and exhausts through an opening formed between exhaust collar 28 and pressure cap 32. Also after the solution delivery system is primed, cleaning solution is pumped by pump 64 independent of debris extraction by actuating trigger 74 to open valve 70. 
     In an alternative embodiment, as shown in FIGS. 9, 10 and 11, an exhaust tube 126 has an upper end which terminates inside tank 20 near top 22. A fill tube 144 is provided for filling tank 20 and for providing a passage way for exhausting the exhaust stream which travels up through exhaust tube 126 from exhaust outlet 110. A fill cap 146 is also provided and has a generally centered stem 134 which has a generally centered aperture through which one end of solution suction hose 48 extends to the bottom 24 of tank 20. Fill cap 146 also has a series of exhaust passage apertures 130 which are spaced about the periphery of stem 134 and allow the exhaust stream to escape from tank 20. A flat washer-shaped pressure cap 132 is slip fit around cap stem 134 so that pressure cap 132 can freely slide up and down cap stem 134. A flange 136 circumscribes cap stem 134 near the top end of stem 134 to retain pressure cap 132 on stem 134. As with the previously disclosed embodiment, tank 20 can be pressurized for priming the solution dispensing system by exerting a downward force upon pressure cap 132 to position pressure cap 132 in sealing contact with exhaust apertures 130. Conversely, releasing pressure cap 132 will allow the exhaust stream to lift cap 132 until it engages flange 136 and the exhaust stream can flow freely between exhaust apertures 130 and pressure cap 132. 
     The above description is considered that of the preferred embodiment only. Modifications of the invention will occur to those who make or use the invention. Therefore, it is understood that the embodiment shown in the drawings and described above is merely for illustrative purposes and is not intended to limit the scope of the invention, which is defined by the following claims as interpreted according to the principles of patent law.