Patent Publication Number: US-6209751-B1

Title: Fluid dispenser

Description:
The present invention generally relates to automatic dispensers and more particularly relates to automatic fluid dispensers for providing a metered amount of liquid soap, or the like, on sensing the presence of a user&#39;s hand. 
     Many automatic fluid dispensers have been developed and have general use in restaurants, hotels, theaters, and the like. The dispensers are typically activated by light, such as infrared sensors. Heretofore developed dispensers typically are prone to clogging which renders the dispenser unusable, or leaking, the latter causing an unsafe situation. 
     Further, heretofore developed devices for the automatic dispensing of a measured amount of liquid are prone to falsely sensing the presence of a user and dispensing unwanted soap. 
     It should be easily appreciated that falsely triggered soap, or the like, when disposed on sink surfaces and floors produces slippery, unsafe surfaces which may result in injury to the public. 
     This problem is recognized in U.S. Pat. No. 4,967,935, which attempted to solve the problem of false operation by using an elaborate control drive circuit which included the emission of an optical signal of predetermined wavelengths in the infrared spectrum and of a predetermined configuration along with optical detection means, responsive to the wavelength and configuration of the optical signal, for actuating a timed control signal, in order to apply power to actuate a rotary motor to dispense fluid. 
     Such elaborate control systems still do not solve non triggering due to the presence of dark clothing or dark skin pigmentation. In addition, false triggering is known to occur by light reflected from porcelain sinks, from fluorescent light ballast or from camera flash. 
     The present invention provides for a fluid dispenser utilizing a disposable nozzle system wherein is self-cleaning in order to eliminate the problem of clogging. In addition, a control system to provide for actuating the dispenser which is virtually free of false triggered operation. In addition, the present invention provides for a touch free pumping action to dispense fluids which simulates manually operated fluid dispensers. 
     SUMMARY OF THE INVENTION 
     A fluid dispenser in accordance with the present invention generally includes a reservoir which provides a means for containing a fluid and tubular means, depending from the reservoir, for receiving fluid therefrom by the force of gravity, and for dispensing measured quantities of the fluid. 
     The tubular means generally includes an orifice and a valve seat disposed at a dispensing end of the tubular means. The reservoir means and tubular means may be disposed in a housing and may be removable as an integral unit therefrom. Accordingly, because the orifice and valve seat are replaced by a change of reservoir, possible clogging of the dispensing end of the tubular means due to prolonged use is eliminated. 
     A plunger is provided and slidably disposed within the tubular means for movement between a first and a second position. The plunger includes an opening therethrough for enabling fluid to flow past the plunger and a valve face is provided on the plunger for sealably engaging the valve seat when the plunger is in the first position. 
     A solenoid is provided and disposed in the housing adjacent the tubular means for magnetically engaging and moving the plunger from the first position to the second position upon activation of the solenoid by electrical current. The second position of the plunger is above the first position with the valve face disengaged from the valve seat. Movement of the plunger to the second position causes flow past the plunger into a tubular lower portion. 
     Spring means are provided and disposed within the tubular means for forcing the plunger to the first position upon deactivation of the solenoid means in order to force fluid in the tubular means lower portion through the orifice. Because the spring means is disposed in the tubular means, it is, of course, disposable therewith and, accordingly, problems of the spring fatigue or sticking due to prolonged use, are eliminated. Further, the spring provides sealing pressure between the valve face and the valve seat which prevents any fluid leakage. Thus, a positive shutoff is provided with no subsequent dripping of fluid. 
     Additionally, the valve face and valve seat are self-cleaning due to the mating angular surface structure provided on the valve face and valve seat. The angular surfaces provide a sliding engagement therebetween which expels any coagulated, or hardened, fluid through the orifice. 
     A control means is provided for sensing the presence of a user&#39;s hand beneath the orifice and providing electrical current to the solenoid means for a duration of time. 
     More particularly, the solenoid means has a torroidal shape and is fixed to the housing with the tubular means being removably disposed therethrough. 
     Preferably, the dispenser includes a first one-way valve for preventing fluid in the tubular means lower portion from flowing past the plunger as the plunger moves to the first position and enabling fluid in the tubular means upper portion to flow into the tubular means lower portion as the plunger moves to the second position. 
     Additionally, a second one-way valve is preferably provided for preventing fluid flow out of the tubular means upper portion as the plunger moves to the second position while enabling fluid flow into the tubular means upper portion as the plunger moves to the first position. 
     The control means in accordance with the present invention preferably includes a Theremin antenna for sensing the presence of a user&#39;s hand and, more particularly, the control means may include a second sensor means for sensing the presence of a user&#39;s hand and processing means for providing electrical current to the solenoid means only upon confirmation of both the Theremin antenna and the second sensor means sensing the presence of user&#39;s hand. 
     Preferably, the Theremin antenna is disposed at a bottom of the housing and in a spaced apart relationship with the valve seat and orifice in order to prevent any interference therebetween. An aperture is provided through the Theremin antenna for passage of fluid therethrough. 
     To provide greater coupling, or sensing of a user&#39;s palm, the Theremin antenna may include upstanding portions which, in combination with a relatively horizontal portion, enables the antenna to generally conform to a shape of the user&#39;s palm. 
     The plunger, valve seat an antenna are virtually aligned which enables vertical upward and downward movement of the user&#39;s palm, like a conventional manual pumping of a level, to cause repeated discharge of fluid from the dispenser. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The advantages and features of the present invention will be better understood by the following description when considered in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a perspective view of the present invention; 
     FIG. 2 is a perspective view of the present invention as shown with a case open to show a housing, a removable reservoir, and a dispensing tube attached thereto; 
     FIG. 3 is a cross sectional view of the tubular dispenser shown in FIG. 2, taken along the line  3 — 3 , generally showing a spring and a plunger disposed within the tube; 
     FIG. 4 is a cross sectional view similar to FIG. 3, showing movement of the plunger toward a surrounding magnetic solenoid with a first one-way valve open for enabling fluid flow into a lower portion of the tubular dispenser; 
     FIG. 5 is a cross sectional view similar to FIG. 4, showing the plunger beginning downward movement under the force of the spring, with the first one-way valve closed, and a second one-way valve, at a top of the tubular dispenser, open for enabling flow of fluid into the tube from the reservoir; 
     FIG. 6 is a perspective view of the reservoir and the dispensing tube removed from the housing; 
     FIG. 7 is a cross sectional view of the dispenser in accordance with the present invention more clearly showing the Theremin antenna disposed in a spaced apart relationship with the valve seat and orifice along with a second sensor for confirming presence of a user&#39;s palm, a light sensor suitable for cutting power to the control system in order to preserve electrical power may also be provided; 
     FIG. 8 is a perspective view of the Theremin sensor, or antenna, and a portion of the control means; 
     FIG. 9 is a block diagram of the control system in accordance with the present invention; and 
     FIG. 10 is a schematic diagram of the control system in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION 
     With reference to FIG. 1, there is shown a fluid dispenser  10  in accordance with the present invention generally showing a case  12  which may be opened, as shown in FIG. 2, to access a housing  14  along with a reservoir  16 , the reservoir providing a means for containing a supply of fluid. A tube  20  provides a means for receiving fluid flow from the reservoir  16  by the force of gravity. Preferably the tube  20  is fixed to the reservoir  16  and removable with the reservoir  16  from the housing  14 . Gravitational flow of fluid into the tube  20  eliminates any need for priming the tube as well as eliminating air bubbles as is the case with many prior art devices. 
     The dispensing tube  20  as shown in FIGS. 3-5 includes an orifice  24  along with a valve seat  26  at a dispensing end  28  of the tube  20 . 
     A plunger  30  is slidably disposed within the tube  20  for movement between the first position shown in FIG. 3 and a second position shown in FIG.  5 . The plunger  30  includes an opening  34  therethrough for enabling fluid to flow past the plunger  30  as shown by the arrows  36  in FIG. 4 to enable fluid flow into the lower portion  42  as will be hereinafter discussed in greater detail. A valve face  44  is provided on an end  46  of the plunger  30  for sealably engaging the valve seat  26  when the plunger  30  is in the first position. This valve arrangement adjacent the orifice  24  enables the stoppage of fluid flow without any subsequent dripping of fluid through the orifice  24 , i.e., the valve is self-sealing. 
     As hereinabove noted and shown in FIGS. 3-5, the valve face  44  and valve seat  26  have mating angular surfaces which, by the sliding engagement therebetween, also provides for self-cleaning of the device because any build-up of fluid, or coagulated fluid is forced downward and outward during operation. This structure also provides for subsequent drip free operation. 
     A solenoid, or actuator,  50  is disposed and fixed to the housing  14  and adjacent the tube  20  to provide a means for magnetically engaging and moving the plunger  30  from the first position, as shown in FIG. 3, to the second position, as shown in FIG.  5 . An interim position of the plunger  30  is shown in FIG.  4 . Operation of the dispensing tube  20  will be hereinafter discussed in greater detail. 
     The solenoid is activated by an electrical current to move the plunger  30  to the second position, which is above the first position, and in which the valve face  44  is disengaged from the valve seat  26 . Movement to the second position causes fluid flow past the plunger  30  into the tubular means lower portion  42 , as shown by the arrow  36  in FIG.  4 . 
     Preferably, the solenoid  50  is in the shape of a torroid which enables easy removal of the tube  20  therefrom when replacing the reservoir attached thereto. Alternatively, the reservoir may be manually refilled in situ, if desired. However, reliable dispensing fluid is best achieved when the reservoir  16  and  20  are removed from the housing  16  and replaced with a full reservoir  14 . 
     A spring  54  disposed within the tube  20  provides a means for forcing the plunger  30  from the second position to the first position upon deactivation of the solenoid  50  in order to force fluid in the tube lower portion  42  through the orifice  24 . Significant advantage is afforded by placement of the spring  54  within the tube  20  because the spring then becomes disposable with the reservoir  16  and tube  20 . Consequently, malfunction of the spring  54 , or deterioration of its properties over time, due to use or through contact with the fluid, will not occur. Further, a conventional inexpensive metal spring may be used since long term exposure to the fluid will not occur. 
     An additional important function of the spring is for providing a sealing force between the valve face  44  and valve seal  26 , and providing force to ensure that the sliding engagement between the valve face  44  and valve seat  26  expels clotted fluid through the orifice  24 . 
     Control system means  60  (FIG. 9) is provided for sensing the presence of a user&#39;s palm  62  (FIG. 7) beneath the orifice  24  and providing electrical current to the solenoid  50  for a duration of time. As hereinafter discussed in greater detail, the control system may be powered by batteries  62  (FIG. 2) disposed in the housing  14  and interconnected with the solenoid  50  in a conventional manner. 
     With reference to FIG. 4 a first one-way valve  64  may be provided for preventing fluid in the tubular means lower portion  42  past the plunger  30  as the plunger  30  moves to the first position. The valve  64  also enables fluid flow from a tube upper portion  66  into the tube lower portion  42  as the plunger  30  moves to the second position. 
     As shown in FIG. 5, when the solenoid  50  is deactivated, the plunger  30  is at the second position and is forced to the first position by the spring  54 . The closed valve  64  thus ensures that all of the fluid disposed in the tube lower portion  42  is dispensed through the orifice  24 . 
     It should be appreciated that the dispensing action of the tube  20  is effective without the one-way valve  64  in view of the various openings  34 , orifice  24  and tube diameters. However, the most efficient operation is enabled through the use of the one-way valve  64  and a second one-way valve  68  disposed at a top  70  shown in open position. 
     Closure of this valve  68 , as the plunger  30  moves to the second position as shown in FIG. 4, enhances the passage of fluid from the upper portion  66  of the tube  20  to the tube lower portion  42 . Flow into the tube upper portion  66  occurs through the force of gravity and, further, by the drawing action of the plunger  30  as it moves from the second position to the first position, see FIG. 5, as indicated by the arrows  72 . Thus, the valve  68  enhances the dispensing efficiency of the tube  20 . 
     As shown in FIG. 6, the reservoir may include a collapsible bag  76  for accommodating pressure differentials as the fluid passes from the reservoir  16  through the top  70  of the tube  20 . 
     With reference now to FIG. 9, there is shown in block diagram form, the functioning elements of the control system  60  which includes a Theremin antenna  80  and an oscillator  82  which provides a signal upon sensing the presence of a user&#39;s palm  62  to a coil driver  86  which provides electrical current to the solenoid  50 . A complete schematic diagram of the control system  60  is shown in FIG.  10  and further operational details are described in copending patent application Ser. No. 09/395,488. filed on even date herewith and entitled DISPENSING CONTROL SYSTEM. This referenced application is to be incorporated in its entirety for describing a control system  60  suitable for use in the present invention. 
     Basically, the Theremin antenna  80  and oscillator  82  is variable voltage frequency source which produces a variable control frequency as the user&#39;s palm  62  approaches the antenna  80 . (FIG.  7 ). This is utilized by the control system  60  to provide control current to the solenoid  50 . 
     It should be appreciated that the Theremin antenna  80  includes two separated panels  92 ,  94  (see FIG. 8) to establish a capacitance therebetween which is detectably altered in the proximity of the user&#39;s hand  62 . No separate ground is required and accordingly the dispenser  10  may be used at any location. 
     As shown in FIGS. 7 and 8, the Theremin antenna  80  includes spaced apart panels  92 ,  94  and upstanding portions  102  which provides a means for enabling the antenna  80  to generally conform to the user&#39;s palm  62 . This conformation provides enhanced coupling between the user&#39;s palm  62  and the Theremin antenna  80  and accordingly provides greater sensitivity. 
     The plunger  30  and antenna  80  are vertically aligned to enable pump-like movement of the user&#39;s hand, as indicated by the arrow  106 , to cause the control system  60  to provide pulsed electrical current to the solenoid  50  to cause pulsed release of fluid in a manner similar to conventional manual dispenser (not shown) which utilizes an activating lever. 
     In addition, the duration of presence of the user&#39;s palm enables a corresponding duration of electrical current to the solenoid  50  via the control means. This causes the plunger to move to a higher second position which accordingly disposes a larger fluid quantity. 
     A second sensor  94  may be provided which independently detects the presence of the user&#39;s palm. In this embodiment the control system  60  provides a signal to the coil driver  86  only upon confirmation of both the Theremin antenna  80  and the second sensor  94  sensing the presence of a user&#39;s hand  62 . 
     It should be appreciated that the second sensor  94  may be of any type, such as an infrared detection system, ultrasound system, heat detector, audio detector, or a bicolor visible light detector, among others. The independent sensing of a user&#39;s hand and confirmation by the processor ensures that accidental or false signals will not be caused which would result in unwanted dispensing of fluid, as is the case in the prior art fluid dispensers. 
     With the use of batteries  62 , power consumption is of utmost importance and a CdS sensor  100  may be provided to turn off the control system  60  upon low ambient light. Therefore, power is conserved at night or in commercial settings with automatic interior light control. The control system  60  is activated only when a user is present, the user&#39;s presence turning on an interior light in a conventional manner. 
     Although there has been hereinabove described a specific fluid dispenser in accordance with the present invention for the purpose of illustrating the manner to which the invention may be used to advantage, it should be appreciated that the invention is not limited thereto. Accordingly, any and all modifications, variations or equivalent arrangements which may occur to those skilled in the art, should be considered to be within the scope of the invention as defined by the appended claims.