Abstract:
A hand held steam vacuum is provided that is operated by way of a single switch device. The vacuum is generally comprised of a vacuum fan, a water pump, a heating element, and a fluid supply tank in fluid communication with a fluid discharge outlet. In operation, the vacuum fan is operable to suck debris into a collection bowl residing in the vacuum. In addition, the water pump is operable to drive fluid from the fluid supply tank via fluid transport tubes to the fluid discharge outlet, and the heating element is operable to heat the fluid prior to it being discharged from the fluid discharge outlet. A single switch device is configured to control operation of the vacuum fan, water pump and heating element.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to hand held steam vacuums. More particularly, the present invention relates to a hand held steam vacuum that is operated by way of a single switch device.  
         BACKGROUND OF THE INVENTION  
         [0002]    Hand held vacuums which utilize a fluid, such as a liquid cleaning fluid or steam, to enhance cleaning are known. Operation of such vacuums is typically carried out via at least two separate and independent switches: a heater switch and a main function switch. The heater switch may be a rocker type switch for controlling the heater. The heater switch has two switch positions, heater “On” and heater “Off.” The main function switch is a four position slider switch having four different switch positions: “Spray,” “Steam,” “Off,” and “Vacuum.” When the function switch is at the “Vacuum” position, only the vacuum motor operates. When the function switch is at the “Steam” position, the water pump operates at a low speed. When the function switch is at the “Spray” position, the water pump operates at a high speed. When the function switch is at the “Off” position, the vacuum motor and water pump are deactivated.  
           [0003]    Operation of a hand held vacuum using the two switch configuration described above is extremely cumbersome and may result in damage to the item being cleaned. For example, if the user fails to switch the heater to the “On” position before actuating the main function switch to either the “Steam” position or the “Spray” position, the vacuum will discharge cold water onto the item being cleaned, thereby possibly causing damage to the item.  
           [0004]    In addition, the two switch configuration may lead to other problems. Due to the independent operation of the two switches, it is conceivable that the heater may be inadvertently left on. For instance, the operator may slide the main function switch to the “Off” position, and yet fail to turn off the heater. Leaving the heater on for a prolonged period of time may damage the heater and possibly shorten the life of the heater and components of the vacuum associated with the heater. Consequently, a need exists in the art to develop a hand held steam vacuum that eliminates the possibility of producing a cold water spray when steam is desired and only allows the heater to be energized when used in the “Steam” and “Spray” modes of operation.  
         SUMMARY OF THE INVENTION  
         [0005]    In accordance with the present invention, a hand held steam vacuum is provided that uses fluid, such as water, to enhance the cleaning of a surface. The vacuum includes a pump to drive the water through fluid transport tubes to a fluid discharge aperture. Before reaching the fluid discharge aperture, the fluid transport tubes direct the water near a heater that heats the water to produce water vapor that is released from the vacuum. The operation of the water pump and heater is controlled by a single switch device preferably having four switch position: vacuum, off, steam, and spray.  
           [0006]    When the switch is placed at the vacuum position, a vacuum fan is activated, but a heater and water pump remain in an inactivated state. When switch is placed in the steam position, the heater is activated and the water pump pumps at a first pumping rate, but the vacuum fan is deactivated. When the switch is placed in the spray position, the heater remains activated and water is pumped by the water pump at a second pumping rate that is different from the first pumping rate. When the switch is placed in the off position, all of the functions are deactivated.  
           [0007]    The use of a single control device to operate the hand held vacuum is advantageous as it prevents the user from accidentally causing damage to the item being cleaned. For example, the use of a single control device makes it impossible to activate the pump without also activating the heater, thus eliminating the possibility of ejecting cold water upon the surface being cleaned due to the operator&#39;s failure to activate the heater in conjunction with the pump. Further, the use of a single control device does not allow the heater to remain energized once the steam or spray operations have ceased.  
           [0008]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a perspective view depicting an exemplary hand held steam vacuum in accordance with the present invention;  
         [0010]    [0010]FIG. 2 is a cross-sectional view of a fluid supply tank employed by the of the hand held steam vacuum of the present invention;  
         [0011]    [0011]FIG. 3 is diagram illustrating switch positions for an exemplary switch device employed by the hand held steam vacuum of the present invention; and  
         [0012]    [0012]FIG. 4 is a schematic of an exemplary pump flow rate control circuit used by the hand held steam vacuum of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0013]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. For example, although the invention is discussed herein in terms of a hand held vacuum that is capable of cleaning a surface using steam generated by heating water, the vacuum may also be configured to clean a surface using other fluids that enhance cleaning.  
         [0014]    Referring to FIG. 1, a preferred embodiment of a hand held steam vacuum, generally indicated at  10 , is illustrated. Hand held steam vacuum  10  generally includes a main body housing  12  to which a collection bowl  14  and a fluid supply tank  16  are removably attached. Housing  12  includes a handle  18  for carrying and manipulating hand held steam vacuum  10 . Internal to the housing  12  is a fan  20 , a pump mechanism  22 , and a heating mechanism  24 . Fan  20 , pump  22 , and heating mechanism  24  are all electrically connected to power supply cord  26  and are operated using a single switch  28 . Fluid is pumped by the pump mechanism  22  from the fluid supply tank  16  through the heating mechanism  24  and out through discharge apertures  30  via fluid transport tubes  32 . Heating mechanism  24  is adapted to heat at least a portion of the fluid flowing from the supply tank  16  to the discharge apertures  30  into steam.  
         [0015]    The debris collection bowl  14  is removably attached to the housing  12  and includes a vacuum inlet  38 , a deflector  40 , and a filter mechanism  42 . During operation, fan  20  sucks air, fluid and debris into collection bowl  14  through vacuum inlet  38 . The incoming materials impact upon deflector  40  which generally separates the fluid and debris from the air that passes through the filter mechanism  42  and out of the housing  12 .  
         [0016]    Referring to FIGS. 1 and 2, the fluid supply tank  16  generally includes a container member  44 , an internal rigid member  46 , and a lid member  48 . Internal rigid member  46  is fixedly attached to the inside surface of lid member  48 . Thus, a fluid passage is provided from a distal end  50  of a rigid flow path extension  52  to a point adjacent fill opening  54  of the fluid supply tank  16 . Fill opening  54  is sealed by a closure  56 .  
         [0017]    Referring to FIG. 2, the fluid supply tank  16  is illustrated attached to the housing  12  of the hand held vacuum  10 . The housing includes mating wall  12 ′ which includes locking tabs  58 . Locking tab  58  is cantilevered from the mating wall  12 ′ and includes a pushbutton  60  which when manually pressed releases fluid supply tank  16  from the housing  12 . Thus, the fluid supply tank  16  is removably connected to main body housing  12  and may be selectively located in position attached to the housing  12  or in an unattached position.  
         [0018]    Attached to mating wall  12 ′ is fluid transport tube  32  and coupling member  62  which are retained together by compression banding  64 . As fluid supply tank  16  is attached to housing  12 , coupling member  62  protrudes into closure  56 . As coupling member  62  continues to protrude into closure  56 , it contacts valve member  66  and opens valve mechanism  68  against the force of biasing member  69 . Thus, attachment of fluid supply tank  16  to main body housing  12  causes coupling member  62  to move valve mechanism  68  into an open position.  
         [0019]    The distal end  50  of the rigid flow path extension  52  is located in the area which is a low point within the fluid supply tank  16  during normal operation of the hand held steam vacuum  10 . Under influence of pump mechanism  22 , fluid is a sucked from the distal end  50  of the flow path extension  52  to radial inlet  70 . Next, fluid passes through the discharge flow path  74  which extends between radial inlet  70  and axial outlet  76  via the bottom segment of recess  78  and past valve mechanism  68 . Coupling member  62  relieves fluid exiting discharge flow path  74  of closure  56  and transfers fluid to pump mechanism  22  via fluid transport tube  32 . Under influence of pump mechanism  22 , the fluid then passes through fluid transport tubes  32  to heating mechanism  24 .  
         [0020]    In operation, a control device, such as a slide type switch  28 , is used to select the mode of operation for the vacuum  10 . Referring to FIG. 3, the switch  28  may take the form of a four position slide switch. Each of the switch positions represent a different mode of operation which may be activated by the switch  28 . In particular, the switch  28  provides a “vacuum” position  82 , an “off” position  84 , a “steam” position  86 , and a “spray” position  88 . The control device for the vacuum  10  may also include a visual indicator  80 , such as a LED, which illuminates during certain modes of operation. In particular, the visual indicator indicates when the heater is energized. The operation of the vacuum is further described below. While the following description is provided to reference to a particular switch configuration, it is readily understood that other switch functions as well as other types of switches are within the broader aspects of the present invention.  
         [0021]    Initially, the switch  28  is in an “Off” position, thereby indicating the vacuum is in an inactive state. When the switch  28  is set to the “Vacuum” position  82 , the vacuum fan  20  will be activated so as to suck debris into collection bowl  14  through vacuum inlet  38 . However, the pump  22  and the heater  24  remain off. Similarly, the visual indicator  80  is not illuminated when the switch is set to the “Vacuum” position. When the switch  28  is placed in the “Steam” position  86 , the pump  22  and the heater  24  are activated; whereas the vacuum fan  20  is deactivated. More specifically, the pump  22  is operated at a first pump speed. Since the heater  24  is on, the visual indicator  80  is also illuminated. It is important to note that the heater was not activated through the use of an independent switch mechanism. Likewise, when the switch  28  is placed in the “Spray” position, the pump  22  and the heater  24  are activated; whereas the vacuum fan  20  remains deactivated. In this case, the pump is operated at a second pump speed that is preferably faster than the first pump speed in the “Steam” position. Again, the visual indicator is illuminated to indicate that the heater  24  is on. If the switch is slid from the “Spray” position to the “Steam” position, the pump  22  will operate at the first pump speed and the heater and visual indicator will remain on. Lastly, if the switch is moved back to the “Off” position, all of the functions will be terminated.  
         [0022]    In the steam mode or spray mode of operation, it is readily understood that the water pump  22  does not operate at a constant rate but rather operates at a variable rate. To control the pump rate, the vacuum  10  further includes a pump flow rate control circuit. A schematic of a preferred pump flow rate control circuit  90  is provided in FIG. 4. The flow rate control circuit  90  is primarily comprised of a timing circuit which is disposed between the switch  28  and the water pump  22 . In the preferred embodiment, a D-type flip-flop circuit  92  provides the pump rate signal to the pump. It is readily understood that additional circuitry may be needed to operate the vacuum fan  20 . Moreover, it is readily understood that other configurations for the control circuit are also within the broader aspects of the present invention.  
         [0023]    In operation, two potentiometers  94  may be used by the operator to manually adjust the set point value for the timing circuit, thereby dictating the pump rate. In the preferred embodiment, the clock signal for the timing circuit is derived from the AC power signal input into the vacuum. Since the frequency of a typical AC power signal is 60 hertz, it is readily understood that the pump rate may be set to within 16.7 milliseconds of the desired pump rate. To improve the accuracy of the desired pump rate setting, the flow rate circuit  90  of the present invention introduces a full wave rectifier  96  as shown in FIG. 4. The full wave rectifier  96  effectively doubles the frequency of the clock signal input into the timing circuit, thereby enabling the pump rate to be set within 8.3 milliseconds of the desired pump rate. To absorb the inductance associated with the pump, a diode  97  may be connected across the pump  22  as shown in FIG. 4.  
         [0024]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.