Abstract:
An electrically operated pre-mix valve includes a cup lever operable to activate a switch to energize a solenoid. The solenoid operates a first lever, which then contacts and operates a second lever. The second lever, in turn, moves against the contact end of an actuating shaft. The actuating shaft is thereby moved to permit beverage flow through the valve and out of a nozzle thereof. Thus, the valve herein uses a compound lever system to gain a mechanical advantage for substantially lessening the opening force required to be applied by the solenoid.

Description:
This application claims the benefit of Provisional Application No. 60/147,239, filed Aug. 4, 1999 
    
    
     BACKGROUND OF THE INVENTION: 
     1. Field of the Invention 
     The present invention relates generally to pre-mix beverage dispensing valves and more particularly to solenoid operated beverage dispensing valves. 
     2. Background 
     Pre-mix beverage dispensing valves are well known in the art, and serve to dispense carbonated drinks such as soda pop and beer. These valves are designed to dispense a carbonated drink with a minimum of carbonation loss, to the atmosphere and by minimizing foaming. This result is accomplished primarily with a compensator positioned upstream of the valve seat that helps to reduce the pressure on the pre-mix, generally 50 to 80 pounds per square inch, to that of atmosphere. Prior art pre-mix valves have typically been manually operated wherein a lever is pulled toward the operator to dispense a drink. A spring provides for assisting in moving the valve back to the closed position and maintaining the valve closed and seated. 
     Various attempts have been made at making a pre-mix valve electrically operable, such as through the use of a solenoid. However, the initial force needed to overcome the pressure on the pre-mix beverage, as well as that of the shaft spring, has presented problems. An electrically operated valve is seen in U.S. Pat. No. 4,708,155 wherein a leveraged solenoid system utilizing a spring linkage is used to reduce the size and power consumption of the solenoid. However, further improvements involving lessening of the initial force required to open a pre-mix valve are required to insure long term reliable operation. 
     SUMMARY OF THE INVENTION 
     The present invention comprises a solenoid operated pre-mix beverage dispensing valve having low opening force requirements. The valve includes a valve body having an actuating shaft slideably mounted along a central axis thereof. The shaft includes a first contact end extending outward of a front end of the valve, and a second end positioned within the valve body. A spring is positioned around the shaft first end and between a spring retainer and the valve body. The valve body includes a radiussed circular seat surface tapering to a smooth cylindrical surface area. A quad-ring is retained in an annular grove extending around the actuating shaft and provides fluid tight sealing between the actuating shaft and the cylindrical surface area of the valve body. The actuating shaft also includes four stop tabs extending radially and equidistantly from and around a common perimeter of the actuating shaft. In the closed position of the valve the four tabs are in contact with the radiussed surface of the valve body and the quad ring is in sealing relationship with the cylindrical valve body surface. 
     A compensator housing is secured to an attachment end of the valve body and a compensator is positioned within the housing. The compensator includes a cylindrical bore for sealably receiving the second end of the actuating shaft. A further quad ring extending around the second end of the actuating shaft provides for fluid tight sealing between the second end and the compensator bore. An air pressure equalization channel extends axially through the center of the actuating shaft and provides air communication between the compensator bore and a transverse channel in the valve body. The transverse channel provides air communication to ambient air pressure. 
     A frame is secured to the exterior of the valve body and the frame structure provides for pivotal mounting thereto of a first lever arm. A second lever arm is pivotally secured to the frame and has a first end positioned between the first lever and the contact end of the actuating shaft. A solenoid is secured to a top surface of the valve body and includes an armature having an external end thereof for engaging with the first end of the first lever arm. A cup contact lever is pivotally suspended below the valve body and is operable to actuate a switch for energizing and de-energizing the solenoid. 
     In operation, the cup lever is moved to operate the switch, which then energizes the solenoid. The armature is then drawn into the solenoid thereby operating the first lever. The first lever then contacts the second lever which, in turn, moves against the contact end of the actuating shaft. The actuating shaft is made to then move against the biasing force of the spring and move the first quad-ring out of contact with the valve cylindrical surface and the four stop tabs out of contact with the radiussed surface. As a result thereof, beverage is permitted to flow between the actuating shaft and the valve body to the dispense nozzle. 
     Those of skill will recognize that the valve of the present invention uses a compound lever system to gain a mechanical advantage for substantially lessening the force required to initiate dispensing. In addition, the air pressure equalization system is improved over the prior art to further lessen the initial force required to open the valve. As a result of the lessened opening force, a lower power solenoid can be used resulting in a substantial increase in the reliability and longevity of the valve. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     A better understanding of the structure, function, operation and advantages of the present invention can be had by referring to the following detailed description which refers to the following drawing figures, wherein: 
     FIG. 1 shows a perspective view of the present invention. 
     FIG. 2 shows a further perspective view of the present invention with the valve cover removed. 
     FIG. 3 shows an enlarged partial cross-sectional reverse angle perspective view. 
     FIG. 4 shows a cross-sectional view of the valve body and components internal thereto in the closed position. 
     FIG. 5 shows a cross-sectional view of the valve body and components internal thereto in the open position. 
     FIG. 6 shows a perspective end view of the valve body. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The valve of the present invention is seen in the various figures and generally referred to by the numeral  10 . As seen in FIGS. 1 and 2, valve  10  includes an outer housing  12  releasably securable to a base plate  14 . As also seen by referring to FIG. 3, removal of housing  12  reveals the pre-mix valve body  16 . Valve body  16  is secured to a frame  20  which is, in turn, secured to plate  14 . A secondary or cosmetic nozzle  22  is securable to plate  14  and is positioned to receive through a central hole thereof the nozzle outlet portion  24  of valve body  16 . A solenoid  26  is secured to a top portion of frame  20  and is held closely against valve body  16 . A registering pin  27  provides for the correct positioning of solenoid there against. An actuating lever  28  is pivotally secured to base plate  14  and depends there below. Lever  28  includes an offset end portion  28   a  that is positioned above and through plate  14  and serves to directly contact and operate a switch  30 . Switch  30  includes contacts  30   a  for connection to wiring, not shown, and serves to energize and de-energize solenoid  26 . Solenoid  26  includes an armature  32  that operates horizontally and is connected to a first lever  34  through engagement with a top end  34   a  thereof. Lever  34  is pivotally secured by a hinge  36  to a bottom portion of frame  20 . A second lever  38  is pivotally secured by a hinge  40  from and below a top portion of frame  20 . Lever  38  includes a contact bead portion  38   a  oriented towards and adjacent a back surface of lever  34 . 
     A seen in FIGS. 4-6, valve body  16  include a valve shaft  46  extending axially through a central bore  48 . Shaft  46  includes a first end receiving a screw  50  therein. Screw  50  secures a spring retaining plate  52  to shaft  46  which serves to retain a spring  54 , extending around shaft  46 , between a front end of valve body  16  and plate  52 . A vertical bore  56  extends through shaft  46  and is in fluid communication with a horizontal axial bore  58  extending centrally through a portion of shaft  16 . Valve body  16  includes an upper bore  61   a  there through providing fluid communication with bore  56  and ambient air pressure. A further lower bore  61   b  extends through valve body  16  and provides for fluid communication between bore  56  and a beverage channel  62  that extends centrally of nozzle portion  24 . A sealing quad-ring  63  extends through an annular groove in shaft  46  adjacent bore  56  and provides for fluid tight sealing with a forward cylindrical inner perimeter surface portion of bore  48 . A second sealing quad-ring  64  extends around shaft  46  and provides for sealing with a rearward cylindrical inner perimeter surface portion of bore  48 . A reduced diameter portion  66  of shaft  46  extends between sealing rings  63  and  64  and defines a flow space  67 . Bore  48  terminates with a radiussed perimeter surface  68 . 
     As best seen by referring to FIG. 6, shaft  46  includes four stop tabs  69  extending axially therefrom around a perimeter thereof adjacent ring  64 . Shaft  46  includes a cylindrical end portion  70  including a third sealing quad-ring  72 . End portion  70  is received in a central axial bore  74  of a compensator  76 . As is known in the art, compensator  76  is retained in a compensator housing  78 . A connecting tube  80  extends around housing  78 . As is known in the art, tube  80  and housing  78  are tightly and sealingly held against valve body  16  by a threaded ring nut  82 . As is also understood, tube  80  provides for securing of valve  20  to a beverage dispenser, not shown. As is further understood, an inlet  84  of compensator housing  78  provides for fluid tight securing of housing  78  to a source of beverage. A fluid pathway  86  exists between the outer surface of compensator  76  and an internal surface of compensator housing  78 . As is known, this flow space is maintained by a plurality of spacing nubs  88  extending from the surface of compensator  76 . Also, as is known, compensator  76  is positioned a desired distance away from perimeter surface  68  by a threaded pin  90  received in valve body  16 . 
     In operation, it can be understood that movement of lever  28  by placement of a cup there against operates switch  30  to activate solenoid  26 . Armature  32  retracts in the direction of arrow A in FIG. 3, moving lever arm  34  to contact bead portion  38   a  of arm  38 . Arm  38  is, in turn, caused to move against screw  50  thereby moving shaft  46  in the direction of arrow B of FIG. 4 to the open position of valve  10 , as depicted therein. Quad ring  72  is moved away from contact with surface  68  thereby breaking the seating there between and permitting the flow of beverage out nozzle  24 . In particular, and as is known, beverage flows into housing  78  and between compensator  76  and housing  78  past surface  68  and into cavity  67 . From there, the beverage flows through channel  62  and ultimately out of nozzle  24  into the cup positioned there below. Upon filling of the cup, it is withdrawn allowing lever  28  to return to its normal position as seen in FIG,  2 . Switch  30  is then disengaged and armature  32  extends in the direction of arrow C of FIG.  3 . Those of skill will appreciate that shaft  46 , under the energy of previously compressed spring  54 , moves in the direction of arrow D of FIG. 5, to the closed position of valve  10  as depicted therein. 
     It was found that solenoid  26  could be relatively small, both in physical size and power rating, yet provide for easy actuating of valve  10 . Such reduced force requirement is due  9  in large part to the leverage advantage provided to solenoid  26  by the compound lever structure represented by lever arms  34  and  38 . In addition, the lower operating force is provided in part, as is known in the art, by a pressure compensating system represented by central shaft channel  58 , bores  61   a ,  61   b , and  56  and compensator recess area  74 . 
     In the prior art, the valve seat between the central shaft and the valve body was created by a circular resilient surface at the end of the central shaft held at an angle sympathetic with an inclined perimeter surface similar to surface  68 . However, over time it was found that some wearing and “plastic” movement would occur such that the central shaft would seat at a position further and further inward of the perimeter surface in the direction of beverage flow. As a result thereof, the operation energy required to unseat the valve would increase. It can be appreciated that tabs  69  serve to prevent such movement and keep the seating position at the same linear point along shaft  46 . In addition, tabs  69  permit the use of a quad-ring as the resilient seating surface interacting with the parallel surface of the shaft bore  48 . This form of more parallel or sliding seating contact also represents less energy to overcome as opposed to the prior art seating where there is direct or normal pressure contact between the seat and the moving valve structure surfaces. As is understood in the art, bores  61   a ,  61   b  and  56  also provide for full drainage of channel  62  by opening thereof to ambient when shaft  46  is in the closed position depicted in FIG.  5 . 
     In a particular preferred valve embodiment a 24 VAC, 50/60 Hz. input power source is used rectified to 24 VDC to operate a linear solenoid. That valve is designed to provide for a nominal fluid flow rate of 1½ to 2 ounces per second with a nominal static pressure of 50 to 60 pounds per square inch. 
     From FIG. 1, it can be appreciated by those of skill, that the smaller solenoid permits the use of an outer housing  12  sized and shaped equivalently to known post-mix valves as, for example, manufactured by IMI Cornelius of Anoka, Minn. Of course, the upright manual operating handle is eliminated as well. Thus, valve  10  has the cosmetic appearance of a post-mix valve which appearance is further enhanced by nozzle  22  and cup activation operation as with lever  28 . Naturally, those of skill will understand that solenoid  26  can also be activated, for example, by a push button switch located on the exterior of housing  12 .