Title:
Automatic drink dispenser
United States Patent 3916963


Abstract:
An automatic drink dispenser for filling cups with liquid when placed in receiving position on a support platform and including a solenoid controlled valve for dispensing liquid into said cups comprises at least one contact member positioned to make contact with the liquid dispensed into said cup in said receiving position when the liquid reaches a predetermined level therein and means electrically interconnecting said contact member and said solenoid control valve for controlling said valve to stop the flow of liquid when the liquid reaches a predetermined level in the cup.



Inventors:
MCINTOSH LAWRENCE D
Application Number:
05/478895
Publication Date:
11/04/1975
Filing Date:
06/13/1974
Assignee:
ROLAR, INC.
Primary Class:
Other Classes:
141/95, 141/361, 141/367
International Classes:
B67D3/00; (IPC1-7): B65B3/26
Field of Search:
141/94,95,96,100,105,193,198,250,283,267,351-362,367,373,378,206,208,209,218
View Patent Images:



Primary Examiner:
Bell Jr., Houston S.
Attorney, Agent or Firm:
Mason, Kolehmainen, Rathburn & Wyss
Claims:
What is claimed as new and desired to be secured by Letters Patent of the United States is

1. In combination with a soft drink dispenser of the type having a solenoid controlled dispensing valve for discharging liquid into a cup placed in a receiving position, a control unit comprising probe means for making contact with the liquid dispensed into a cup placed in said receiving position when said liquid reaches a predetermined level in said cup, first means actuated by said probe means upon movement of a cup into said receiving position for actuating said solenoid controlled dispensing valve of said dispenser to discharge liquid into said cup and second means actuated by the contact of said liquid in said cup with said probe means when said liquid reaches said predetermined level for actuating said solenoid controlled valve of said dispenser to shut off the discharge of liquid.

2. The apparatus of claim 1 wherein said probe means comprises a pair of spaced apart probes having lower end portions for contacting said liquid in said cup and pivotally supported above said cup for pivotal movement upon engagement by a cup moved transversely thereof into said receiving position.

3. The apparatus of claim 2 wherein said probes hang downwardly in a normal position when not engaged with a cup and are pivotally moved to a switch activating position by engagement of said lower end portions thereof with a cup moved transversely against said probes.

4. The apparatus of claim 3 wherein said first means includes switch means activated by the pivotal movement of said probes from said normal position to said activating position for initiating the discharge of liquid into said cup placed in said receiving position.

5. The apparatus of claim 3 wherein said lower end portions of said probes are formed in an S-shape with a lower leg for contact with the liquid in a cup for one height and a curved segment interconnecting said lower leg with an upper portion thereof for contact with the liquid in a cup of greater height at a higher level.

6. The apparatus of claim 4 including an actuator connected with an upper portion of said probes eccentric of the point of pivotal support thereof for engaging said switch means to operate the same when said probes are moved to said activating position.

7. An automatic dispenser for filling cups with liquid comprising means for supporting said cups in position to receive said liquid, a liquid dispenser including a nozzle spaced above said cup supporting means and including a solenoid controlled valve for controlling the dispensing of liquid into a cup placed in said receiving position, at least one contact member positioned to make electrical contact with the liquid dispensed into a cup in said receiving position when said liquid reaches a predetermined level, means activated by the placement of a cup in receiving position on said supporting means for actuating said solenoid controlled valve to dispense liquid into said cup, and control circuit means electrically interconnecting said contact member and said solenoid controlled valve for actuating said valve to stop the dispensing of liquid into a cup in said receiving position when the liquid attains said predetermined level in said cup for making electrical contact with said contact member.

8. The dispenser of claim 7 including a pair of spaced apart contact members for making contact with said liquid dispensed into said cup in said receiving position whereby electrical current is carried through said liquid between said members.

9. The dispenser of claim 7 wherein said control circuit means includes switch means for initiating the dispensing of liquid and mechanically actuated by said contact member when a cup is moved into contact therewith during placement in said receiving position.

10. The dispenser of claim 8 wherein each of said contact members include first and second contact areas spaced at different levels for making contact with the liquid adjacent said different levels when contained in cups of different capacity.

11. An automatic control system for installation on a liquid dispenser of the type having a solenoid controlled dispensing valve for discharging liquid into a cup placed in a receiving position on a support member, said system including a control circuit comprising probe means attachable on said dispenser for making contact with the liquid dispensed into a cup placed in said receiving position when said liquid reaches a predetermined level in said cup, first means mechanically actuated by said probe means upon movement of a cup into said receiving position for electrically controlling said solenoid controlled dispensing valve of said dispenser to discharge liquid into said cup and second means electrically actuated by the contact of said liquid in said cup with said probe means when said liquid reaches said predetermined level for controlling said solenoid controlled valve of said dispenser to shut off the discharge of liquid.

12. The apparatus of claim 11 wherein said probe means comprises a support bracket removable attached to said dispenser and a pair of spaced apart probes having lower end portions for contacting said liquid in said cup and pivotally supported on said bracket above said cup for pivotal movement from a first position to a second position upon engagement by a cup moved transversely of said probes into said receiving position on the support member of said dispenser.

13. The apparatus of claim 13 wherein said probes hang freely downwardly in said first position while not engaged with a cup and are pivotally moved to said second position by mechanical engagement of lower end portions of said probes with a cup moved transversely against said probes into said receiving position on said support member of said dispenser.

14. The apparatus of claim 13 wherein said first means includes switch means activated by the pivotal movement of said probes from said first position to said second position for initiating the discharge of liquid into said cup placed in said receiving position.

15. The apparatus of claim 13 wherein said lower end portions of said probes are formed in an S-shape with a lower leg for contact with the liquid in a cup of one height and a curved segment interconnecting said lower leg with an upper portion thereof for contact with the liquid in a cup of greater height at a higher level.

16. The apparatus of claim 14 including an actuator connected with an upper portion of said probes eccentric of the point of pivotal support thereof for engaging said switch means to operate the same when said probes are moved to said activating position.

17. The apparatus of claim 12 wherein said probes are detachably supported from said support bracket, said support bracket including means for securing the same to said dispenser at a selected level in a range of levels above said support member of said dispenser for accommodating cups of different heights.

18. The apparatus of claim 11 wherein said control system includes a housing detachably mounted on said dispenser and circuit means connectable with said solenoid controlled valve of said dispenser for push button control of the same to start and stop the dispensing of liquid into a cup placed on said support platform.

19. Apparatus for automatically controlling the flow of liquid dispensed through a solenoid controlled valve into a cup placed in a receiving position, said apparatus including first means activated by the placement of said cup in said receiving position for initiating the flow of liquid dispensed through said valve and second means including a pair of contact members positioned to establish a path for electrical current therebetween through the liquid dispensed into said cup in receiving position when said liquid reaches a predetermined level in said cup for activating said valve to shut off the flow of liquid therethrough.

20. The apparatus of claim 19 wherein said contact members include lower contact areas adapted to make electrical contact with said liquid reaching said predetermined level in said cup and upper contact areas spaced upwardly of said lower areas for making electrical contact with the liquid in a taller cup placed in receiving position when said liquid reaches a second level spaced above said predetermined level.

21. The apparatus of claim 20 wherein said lower contact areas of said contact members are offset horizontally of said upper contact areas to clear the interior of a taller cup placed in receiving position.

22. The apparatus of claim 21 wherein said lower and upper contact areas of each contact member are formed of a continuous electrically conductive probe in a substantially S-shaped configuration.

23. The apparatus of claim 19 wherein said means for initiating the flow of liquid comprises a depending lever pivotally supported for actuating a switch when a cup is placed in said receiving position, said control apparatus comprising means for detachably supporting said contact members from said lever for making contact with the liquid dispensed into said cup.

24. The apparatus of claim 23 wherein said means for detachably supporting said contact members is adjustably positioned on said lever for adjusting said predetermined level.

25. The apparatus of claim 23 wherein said contact members are detachably supported from said supporting means.

26. The apparatus of claim 19 further comprising a relay having a relay coil and normally closed contacts connected in circuit with said solenoid controlled valve, means connected to said relay coil for energizing said coil, means for interrupting the energization of said relay coil in response to the operation of said cup placement activated means, and means responsive to said electrical contact through said liquid for re-energizing said relay coil.

27. The apparatus of claim 26 wherein said relay coil energizing means includes a controlled rectifier having main electrodes connected in series with said relay coil and a control electrode, said interrupting means includes switch means activated by said cup placement activated means connected in circuit with said controlled rectifier for interrupting the flow of current through said controlled rectifier upon activation thereof, and said electrical contact responsive means includes transistor means electrically coupled to said contact members and said control electrode, said transistor means being responsive to electrical contact through said liquid for rendering said controlled rectifier conductive.

28. The apparatus of claim 27 further including second manually operable means for interrupting the flow of current through said controlled rectifier, and manually operable switch means for rendering said controlled rectifier conductive.

Description:
The present invention relates to an automatic dispenser for filling cups or other receptacles with liquid such as soft drinks, coffee and the like and more particularly, relates to an automatic dispenser system of the type wherein once a dispensing cycle is initiated, flow is continued until the liquid reaches a predetermined level in a receptacle or cup.

Many beverage and liquid dispensing devices are available today for dispensing carbonated beverages, juices, coffee, iced tea and other liquids into waiting containers or cups placed in a receiving position. These prior art dispensers generally include a support platform having grating for draining excess liquid and supporting the cups or receptacles while they are being filled. The liquid is dispensed from a control head spaced upwardly above the support platform and containing one or more solenoid controlled valves for controlling the flow of fluid during a dispensing operation. In many carbonated beverage dispensing units, a pair of solenoid controlled valves are utilized, one for controlling the flow of syrup and another for controlling the flow of carbonated water. These solenoid valves are activated by a mechanical lever which is depressed or pivoted by contact with a cup placed in receiving position. The lever activates a microswitch used for energizing the solenoid windings to open the dispensing valves to dispose liquid into the receiving position. The flow of liquid continues until such time as the cup is manually removed or pulled away from contact with the mechanical lever.

In the fast food industry in particular, there has developed a great need for an automatic dispenser which will fill cups to a predetermined level and then shut off the flow automatically to prevent underfilling or the messy spillage and waste resulting from overfilling cups. Several different types of systems have been tried, however, these systems suffer from numerous drawbacks. One such system uses a time control approach and is ineffective because of different flow rates and pressures encountered and because of different amounts of ice placed in the awaiting cups. Different sizes of cups also present difficulties for a time controlled dispensing cycle. Another system has been tried wherein a metered volume of liquid is dispensed and this system suffers from the drawback that there is no uniformity in the amount or density of ice placed in the awaiting cups (usually a manual operation) and hence a fixed and metered volume of liquid is sometimes less than required to fill a container or in other instances, more than required and causes overfilling and spillage.

The present invention provides an automatic control system for a beverage dispenser which is foolproof in operation and which eliminates the foregoing problems encountered with prior art devices.

It is an object of the present invention to provide a new and improved automatic liquid dispenser for dispensing liquids into receptacles.

It is another object of the invention to provide an automatic liquid dispenser which automatically shuts off the flow of liquid into a cup when the liquid reaches a predetermined level.

It is another object of the present invention to provide a new and improved automatic liquid dispenser which provides for easy and repeated filling of cups or receptacles to a predetermined fill level without requiring operator attention.

Another object of the present invention is to provide a new and improved automatic liquid dispenser which is operable to handle several different fill heights or levels for cups or receptacles of different sizes.

Another object of the present invention is to provide a new and improved automatic liquid dispenser which is reliable in operation, easy to clean and sanitize and which requires little or no operator skill or attention during operation.

Another object of the invention is to provide a new and improved automatic liquid dispenser system capable of both manual or automatic operation.

Another object of the present invention is to provide a new and improved automatic liquid dispenser in accordance with the foregoing object which can be manually operated to start or stop the dispensing of liquid by means of conveniently located push buttons.

It is another object of the invention to provide a new and improved automatic liquid dispenser control system which is compatible with and capable of being easily installed for use with presently existing mechanically actuated dispensers.

Another object of the present invention is to provide a new and improved automatic liquid dispenser in accordance with the foregoing object which utilizes the mechanical lever of an existing device for initiating a dispensing cycle and provides electrical control for shutting off the flow when a desired fill level is reached.

Another object of the present invention is to provide a new and improved automatic liquid dispenser system particularly suitable for rapid installation and integration with presently existing soft drink dispensing devices, which system is relatively low in cost, easy to install and assemble and extremely reliable and foolproof in operation.

Another object of the present invention is to provide a new and improved automatic liquid dispenser system in accordance with the foregoing object which system can be easily turned off if desired to return the original drink dispenser with which the system is integrated to a normal mechanical operation.

Another object of the present invention is to provide a new and improved automatic liquid dispenser employing novel means for automatically filling cups of different sizes.

The foregoing and other objects of the present invention are accomplished in an illustrated embodiment by way of representation and not limitation comprising in combination with a liquid dispenser of the type having a solenoid controlled dispensing valve for discharging liquid into a cup or receptacle placed in a receiving position. The automatic system comprises means activated by the placement of a cup in a receiving position for initiating the dispensing of liquid through solenoid controlled valves and includes liquid contact means for making electrical contact through the liquid dispensed into the cup for controlling the solenoid valve to shut off the flow of liquid when the liquid reaches a predetermined level.

For a better understanding of the present invention reference should be had to the following detailed description taken in conjunction with the drawings in which:

FIG. 1 is a side elevational view, with portions broken away of a soft drink dispenser having an automatic control system in accordance with the features of the present invention;

FIG. 2 is a front elevational view of the apparatus of FIG. 1;

FIG. 3 is a schematic, electromechanical diagram of the automatic liquid dispenser system in accordance with the features of the present invention;

FIG. 4 is an enlarged fragmentary elevational view illustrating electrical contact members or probes in accordance with the invention for providing automatic shutoff when predetermined liquid filling levels are reached;

FIG. 5 is a front elevational view looking in the direction of arrows 5--5 of FIG. 4; and

FIG. 6 is a cross-sectional view taken substantially along lines 6--6 of FIG. 4.

Referring now more particularly to the drawings, therein is illustrated a new and improved automatic liquid dispenser constructed in accordance with the features of the present invention and generally referred to by the reference numeral 10. The dispenser 10 includes a base or cup supporting platform 12 having a liquid drain therein, an upright support post 14 from which is mounted a dispensing head 16 having a lower section 18 and a modified upper or top section 20 constructed in accordance with the features of the present invention. The lower support platform 12 is adapted to support cups 22 and 24 of several different sizes placed in receiving position thereon beneath a liquid mixing discharge funnel 26 having an outlet at the lower end thereof for dispensing a flow of liquid into an awaiting cup.

The lower section 18 of the dispensing head 16 provides support and enclosure for one or more solenoid controlled dispensing valves 28, each having a solenoid winding 28a (FIG. 3) operable to open the valves when energized with current, for example supplied from a 24-volt AC source. In a dispenser for soft drinks and the like one of the solenoid valves may be supplied with syrup through a supply tube 30 which extends rearwardly from the control valve and downwardly through the support post 14 to a source of syrup (not shown). A similar supply line is provided for carbonated water and the syrup and carbonated water are mixed in the dispensing funnel 26 when the respective solenoid controlled valves 28 are open during a dispensing operation. As shown in FIG. 1, the solenoid valves 28 for syrup and carbonated water are arranged in tandem and the syrup and carbonated water discharged through the valves is directed via open ended tubes or conduits 32 as shown schematically in FIG. 3 for mixing in the funnel 26 as the soft drinks are dispensed. In dispensers for beverages other than soft drinks only, one dispensing valve may be required and in other instances, more than a pair of valves may be needed for dispensing the desired number of different fluids.

In prior art devices, the control of fluid dispensing through the solenoid valve 28 is provided by a mechanical actuator lever 34 extending downwardly from the dispensing head 16 toward the support platform 12. The lower end of the lever or an adjustable extension thereon is manually contacted by the placement of a cup 22 or 24 in receiving position. As best shown in FIG. 1, the mechanical lever 24 is pivotable about a rib 36 provided in the lower section 18 of the dispensing head and a bias spring 38 is provided to normally bias the lever in a clockwise direction, as viewed in FIGS. 1 and 4, to a nondispensing or normally shut off position wherein the solenoid windings 28a are de-energized and the respective valves controlled thereby are closed. In the prior art devices, the lever 34 is normally provided with an adjustable lower extension for making direct mechanical contact with the cups. In accordance with the present invention, the adjustable lower lever extension is removed as mechanical holding of a cup against the lever 34 or direct contact between the cup and lever extension is no longer required when the automatic dispensing system is in operation.

The upper end of the lever 34 is adapted to actuate the operator of a microswitch 40 having a common terminal "C", a normally open contact "n.o.," and a normally closed contact "n.c." The windings 28a of the one or more solenoid valves in the dispenser head 16 are each wired in series with the normally open and common contacts of the microswitch 40 (see FIG. 3). In the mechanical mode of operation, when the lever 24 or lever extension is pivoted in a counterclockwise direction as shown by the arrow "A" (FIG. 3) by contact or engagement with a cup the normally open circuit is closed via the microswitch and the solenoid windings 28a are energized to pen the valves and thereby dispense fluid. In the mechanical mode of operation of the prior art, the fluid flow once initiated as described continues until the microswitch is deactivated, usually when an operator manually removes a filled cup. This situation oftentimes resulted in the overflow of cups as operators frequently became busy with other chores or were unattentive. Overflowing liquid causes sanitation problems and economic waste and is carried away to the sewer through the drain in the cup support platform 12.

In accordance with the present invention, the mechanical lever 34 of an existing or prior art drink dispenser (after having the lower lever extension removed therefrom) is utilized for initiating a dispensing cycle when either a large or small cup 22 or 24 is placed in receiving position on the platform 12 by movement of the cup in a lateral direction as indicated by the arrow "B" of FIGS. 1 and 4. A pair of depending contact members or probes 42 are pivotally supported on a common bracket 44, which bracket is removably attached to the mechanical lever 34 at the desired level. As best shown in FIG. 6, the bracket 44 includes a slot 44a for receiving the lever 34 and a removable thumb screw 46 is provided for securing the bracket in place on the lever 34. The depending probes or contact members 42 are preferably formed of stainless steel for sanitary reasons and are adapted to make electrical contact with liquid dispensed into an awaiting cup 22 or 24 placed in a receiving position on the support platform 12 as shown in FIG. 4. The lower end portion of each probe is formed in a modified "S-shaped" configuration as shown and at the lower end 42a or tip the probes make contact with the liquid in a small cup 22 when the liquid level reaches or approaches the upper rim of the cup at a predetermined fill level indicated by the level line "C." In the case of carbonated beverages the bubbles developed on the surface of the liquid filling a cup 22 may make electrical contact with the lower ends 42a of the probes 42 slightly before the liquid level actually reaches the level "C," however, in the case of noncarbonated beverages having relatively few bubbles develop on the surface the liquid normally reaches the level "C" to establish electrical contact through the liquid between the parallel probes.

The difference in fill levels between various types of liquids most commonly dispensed with the device 10 is relatively small and in the most part inconsequential. Upwardly from the lower ends 42a, the probes are provided with relatively straight, short length legs 42b and these legs comprise the base of the generally S-shaped configuration of the probes as best shown in FIGS. 4. The probes 42 provide a mechanical as well as an electrical function and provide a mechanical extension for the actuating lever 34 when installed thereon. When cups 22 or 24 are placed in liquid receiving position on the receiving platform 12 as shown by movement of the cups from left to right in the direction of the arrows "B" the probes are engaged momentarily and the lever 34 moves in a counterclockwise direction. This action causes the common and normally open contacts of the microswitch 40 to close. With a small size cup 22, the upper edge of the rim is momentarily engaged against the legs 42b to pivot the lever 34 and momentarily actuates the microswitch 40. When the cup is released in placed as shown, the lower ends 42a of the probes are extended into the interior of the cup ready for making electrical contact with the liquid dispensed therein when the liquid reaches the predetermined filling level "C." Vertical adjustment of the probe support bracket 44 on the lever 34 by loosening and retightening the thumb screw 46 provides an easy and rapid means for adjusting the height of the filling level "C" above the platform 12. Once the upper lip of a cup 22 is passed under the lower ends 42a of the probes and released to rest in the receiving position as shown, there is no forceful engagement between the probes and the cup and the lever 34 and probes 42 then return to the normal or neutral position under the influence of the bias spring 38. In the neutral position the microswitch 40 is no longer actuated by the upper end of the lever 34. The "S-shaped" portion of the probes 42 provides a secondary, higher level, electrical contact area indicated by the reference numeral 42c for controlling the dispensing of the liquid when filling cups 24 of larger height. This second or higher predetermined filling level is indicated by the level line "D." As larger cups 24 are moved into receiving position on the platform 12 in the direction of the arrows "B" of FIG. 4, the upper edge or lip of the cup is passed under the contact areas 42c and the outside surface of the cup is contacted against the legs 42b momentarily thereby pivoting the lever 34 to momentarily actuate the microswitch 40 as previously described. After the momentary contact between a cup 24 and the probe legs 42b is discontinued by release of the cup to rest in the receiving position as shown, the cup surface may be spaced slightly apart from the legs 42b of the probes (distance "E") so that the bias spring 38 again returns the lever 34 and probes 42 to the normal or neutral position wherein the microswitch 40 is no longer actuated. It should be noted that both the small and large cups 22 and 24 are tilted slightly as they are moved into receiving position on the platform 12 and the arrow "B" indicates the relative path of travel of the cups during this movement. The cups are tilted slightly during movement into the receiving position but when released for filling, the cups rest in the upright position normally spaced apart from the probes mechanically as shown in enlarged detail in FIG. 4. The lower contact areas at the ends 42a of the probes extend into the interior of the small cups 22 ready for terminating the flow at the end of the dispensing cycle when the liquid in the cup reaches or approaches the level "C." Similarly, with the large cups 24, the outer edge of the cup is spaced slightly from the mechanical engagement with the forward edges of the legs 42b of the probes so that the probes 42 and lever 34 may remain in the neutral position during the filling operation in a large cup without maintaining the actuation of the microswitch 40 as the filling operation proceeds.

At the upper end portion, each probe 42 includes a straight section extended upwardly through a passage provided in a support block 48. The support blocks are removably secured for pivotal movement on opposite sides of the probe support bracket 44. As best shown in FIG. 6 a pair of removable thumb screws 50 are provided for securing the probe support blocks 48 to the sides of the bracket 44. In addition to the provision for adjusting the level of the probe support bracket 44 on the mechanical lever 34 by loosening and retightening of the thumb screw 46, each individual probe 42 may be adjusted relative to its support block 48 and for this purpose a transverse set screw 52 is provided. The upper end portions of the probes 42 extend upwardly beyond the upper edges of the support blocks 48 and male or female electrical connectors 54 are mounted on the upper ends of the probes for making electrical contact with appropriate male or female connectors 56 that are provided on flexible control leads 58.

As shown schematically in FIG. 3, and in FIGS. 1 and 4, the leads 58 from the probes 42 extend upwardly into the dispenser control head 16 and pairs of male/female connectors 54 and 56 provide convenient means for connecting and disconnecting the level sensing probes from an electrical circuit board in the control head when it is desired to remove the probes and supporting assembly for cleaning or service purposes. As will be seen in FIG. 4, the upper portions of the probes and the mechanical lever 34 are sloped from the vertical in the normal or neutral position and placement of a large or small cup in receiving position by insertion generally transversely of the probes in the direction of the arrows "B" onto the support platform 12 causes the probes and lever to pivot in a counterclockwise direction indicated by the arrows "A."

The probes are pivotally interconnected with the support bracket 44 by means of the thumb screws 50 but pivotal movement of the probes in a counterclockwise direction relative to the support bracket 44 is prevented by a pair of inwardly directed stop pins 60 which engage surfaces defined by the sides of triangular shaped recess 44b on the rearward edges of side flanges of the bracket. Relative pivotal movement of the probes 42 in a clockwise direction relative to the support bracket is permitted, however as the pins may move out of the recesses and this relative pivotal action permits liquid filled cups 22 and 24 to be removed from the support platform 12 without substantial interference.

Referring now to FIG. 3 and the electrical portion of the schematic diagram therein shown, it will be seen that 24-volt A.C. power is supplied to the one or more solenoid windings 28a (which are connected in parallel) through a pair of A.C. power leads 62 and 64. One lead 62 is connected to one end of the solenoid windings and the other lead 64 is connected to the normally open (n.o) contact of the microswitch 40. The common (c) contact of the microswitch is connected via a lead 66 to the opposite end of the one or more solenoid windings 28a so that any time the manual actuator lever 34 depresses the microswitch the solenoids are energized with 24-volt A.C. power to open the valves 28 controlled thereby and permit fluid flow.

In accordance with the present invention, the lower section 18 of the dispenser control head 16 supports the solenoid valves 28, the microswitch 40 and the mechanical actuator lever 34 along with the probe assembly associated therewith. However, the existing or original equipment upper section of the dispensing head is replaced by a new upper section 20 constructed in accordance with the features of the present invention. The new upper head section 20 is designed and adapted to replace the upper sections originally furnished with an existing dispenser 10 and when replacement is made along with electrical connections and installation of the probe assembly, an existing dispenser is converted rapidly and easily into an automatic unit in accordance with the present invention. As best shown in FIG. 1, the upper section 20 of the dispenser head comprises a housing having a front wall, a back wall and an inverted U-shaped cross-sectioned top and side wall combination secured in place on the lower housing section 18 by a single cap screw 68 which is threadedly received in a bracket 28b normally provided with the dispenser for holding solenoid windings of the valves 28 in place. As indicated in FIG. 2, the front wall of the upper housing section 20 provides a supporting panel for a double pole, single throw, "on-off" switch indicated by the reference numerals 70 in FIGS. 1, 2 and 3. To the left of the switch as viewed in FIG. 2, there is provided a normally closed, pushbutton type, "start" switch 72 and on the right hand side of the switch 70 there is provided a normally open, pushbutton type, "stop" switch 74. The automatic control feature in accordance with the present invention can be locked in or out with the switch 70 and by moving the switch to the "off" position normal mechanical operation of the dispenser with the lever 34 is utilized. In addition, manual electrically controlled operation of the unit can be obtained by starting and stopping of a dispensing cycle with the pushbutton 72 and pushbutton switch 74, respectively.

Referring now to FIGS. 1 and 2, the automatic control system of the present invention includes a circuit generally indicated by the reference numeral 76 (FIG. 3) and preferably provided on printed circuit board 78 mounted in the upper portion of the upper head section 20. Low voltage D.C. power in the order of 41/2 volts may be obtained for operation of the circuit 76 either through a step down transformer 80 and the rectifiers 82 powered from the 24-volt A.C. source used for the solenoid windings 28a and in this case electrical connection to the 24-volt A.C. source within the head 16 may be conveniently made, or a separate source of low voltage D.C. power may be used. When installing the automatic system of the invention on an existing manually operated dispenser the electrical connections are simple to make and are conveniently accomplished.

Positive D.C. voltage is supplied to the circuit 76 through one side (right hand) of the on-off switch 70 and a lead 84 is connected from the switch to one terminal of the normally closed, push button start switch 72. The opposite terminal of the "start" switch 72 is connected via a lead 86 to the normally closed (n.c.) contact of the microswitch 40 in the lower housing section 18 of the dispensing head 16. With the microswitch in the unactuated or normal position, a current path is provided through the normally closed (n.c.) terminal and the common (c) terminal and positive voltage is thus supplied via a lead 88 and branch lead 90 to one side of a relay coil 92. The coil when energized operated to open a pair of normally closed contacts which are wired in parallel with the common (c) and normally open (n.o.) terminals of the microswitch 40 via the lead 88 and a lead 94. The other side of the "on-off" switch 70 is wired in the lead 88 between the common terminal (c) of the microswitch 40 and the right hand contact of the normally closed, relay contacts operationally controlled by the relay coil 92. When the "on-off" switch 70 is moved to the off position, the normally closed contacts of the relay coil 92 can no longer make the circuit to energize the solenoids 28a and only manual operation of the dispenser can be utilized.

The relay coil 92 is parallel with a resistor 96 and is normally energized by a silicon controlled rectifier 98 in order to maintain the contacts of the relay coil 92 open. This allows the solenoid valves 28 to be operated by mechanical actuation of the microswitch 40. The energizing circuit for the relay coil 92 includes the lead 94, the normally closed switch 72, the normally closed contacts of the microswitch 40, the lead 90, the relay coil 92, the anode of the silicon controlled rectifier 98, which is connected to the relay coil 92, and the cathode of the silicon controlled rectifier 98 which is connected to the negative source of direct current potential. When current through the energizing circuit for the relay coil 92 is interrupted by opening either the normally closed "start" switch 72 or the normally closed contacts of the microswitch 40, the silicon controlled rectifier 98 is rendered nonconductive and remains nonconductive until a triggering signal is applied to its gate. When the silicon controlled rectifier 98 is rendered nonconductive, the contacts of the relay coil 92 close to energize the solenoid valves 28 and dispense the beverage.

The triggering of the silicon controlled rectifier 98 is controlled by a transistor 104 having its emitter connected to the gate of the controlled rectifier 98, its collector connected to a source of direct current potential by resistors 106 and 114 and the normally closed contacts of the microswitch 40. The emitter of the transistor 104 is connected to a source of negative potential (lead 100) by means of a resistor 110. A capacitor 108 is connected between the base of the transistor 104 and the source of negative potential to filter out switching transients.

Once the silicon controlled rectifier 98 has been rendered nonconductive to dispense the beverage, the dispensing of the beverage is terminated by again rendering the controlled rectifier 98 conductive. This is accomplished by applying a positive potential to the base of the transistor 104. The positive potential is obtained from the common terminal (c) of the microswitch 40 and may be applied to the base of the transistor 104 by either the "stop" switch 74 or an electrical connection between the probes 42.

In automatic operation, the electrical connection between the probes is provided by the conductivity of the beverage when the liquid reaches the predetermined upper or lower contact areas 42a or 42c of the probes. The stop switch 74 serves to terminate the dispensing of the beverage should the level of the beverage fail to reach the probes for any reason. Alternatively, the "start" switch push button 72 and the stop switch push button 74, which are momentary type switches, may be used to manually control the dispensing operation. In automatic operation, the dispensing operation is initiated by actuating the mechanical lever 34 and terminated by the liquid reaching one of the predetermined levels on the probes dependent on whether a small cup 22 or large cup 24 is placed in receiving position.

Although the present invention has been described with reference to a single illustrative embodiment thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this invention.