Carafe-Operated Coffee Brewing System

1. Field of the Invention

This invention relates to coffee brewing apparatus which allows a brew cycle to be initiated manually upon insertion of a coffee receiving vessel into its coffee receiving position which prevents a brew cycle from proceeding if a plurality of required operating conditions are not implemented.

2. Description of the Prior Art

Numerous efforts have been made over the years to automate coffee brewing apparatus intended for household use. These have often been of complex design utilizing costly components, subject to frequent breakdowns, and requiring frequent and expensive maintenance in order to keep them in operating condition. In a recent instance, U.S. Pat. No. 4,682,537 discloses a commercial vending machine which provides probes arranged at different levels for sensing the amount of brewed coffee remaining. When a tank containing the brewed coffee is approximately one-third full, a "coffee low" light is displayed and a new coffee making cycle may be initiated either automatically of manually.

Another construction for commercial purposes is disclosed in U.S. Pat. No. 4,621,571 which provides a plurality of satellite receptacle units for the storage and dispensing of hot coffee which can be filled from a central brewing unit. A safety switch assembly assures that a brewing cycle cannot be initiated unless the brew chamber is properly aligned to discharge into a correspondingly aligned empty satellite unit.

An automatic household coffee brewing machine is disclosed in U.S. Pat. No. 4,566,802 which is programmable to begin a brewing cycle at a predetermined time, but which assures that an unattended coffee maker is not repeatedly activated thereafter. Thus, after filling the coffee maker with water and ground coffee, the user must manually supply a cycle enable signal, for example, by toggling a switch.

Automatic beverage brewing apparatus is disclosed in U.S. Pat. Nos. 4,608,916, 4,406,217, and 4,468,406, each of which allows a user to choose a desired number of cups of coffee as well as its strength. In U.S. Pat. No. 4,608,916, a plurality of indicator lights indicate no coffee, no water, and used filter, but there is no provision for rendering the apparatus inoperative in the event any of the indicator lights are lighted. In U.S. Pat. No. 4,468,406, there is mentioned, but no disclosure, of a low-water shut-off mechanism and associated alarm.

In U.S. Pat. No. 4,484,515, a sophisticated commercial expresso coffee machine is disclosed which brews coffee pods placed in one or more extraction heads. It includes an electronic control system which operates all functions of the machine including maintaining careful monitoring and control of the water temperature and the volume of hot water delivered to each extraction head. The machine diagnoses itself for possible failures and depleted supplies by showing on a display in code the kind of failure or of needed supply, for example, coffee, water. Each step of an operation is controlled until completion and the machine proceeds to the next only upon confirmation of proper execution of the earlier step. In the absence of confirmation, subsequent operations are not performed. Instead, a digital code signal is displayed in the machine panel corresponding to the failure or depletion in the machine.

Manually initiated coffee brewing apparatus is disclosed in U.S. Pat. No. 4,012,481 which includes a mill mechanism and utilizes a heater circuit containing a cover switch and a pair of other switches which control the heater mechanism. If all switches are closed, once initiated, a brew cycle proceeds to conclusion. Otherwise the apparatus remains inoperative except to digitally display a difficulty, such as "LID", to indicate that the cover is open.

It was the intent of the inventors to improve on known systems of the type just noted. Specifically, it was their intent to provide coffee brewing apparatus incorporating modern features while utilizing a system exhibiting a simplified construction and operation resulting in its being less expensive to manufacture and maintain. These goals have been achieved by reason of the present invention.

To this end, a coffee brewing system is disclosed which enables a brew cycle to be initiated automatically upon insertion of a coffee receiving vessel into its coffee receiving position, but which prevents a brew cycle from proceeding if a number of required operating conditions are not implemented. If all of the operating conditions become implemented again after a brew cycle, once underway, is interrupted, the brew cycle continues on to completion. Visual signals indicate that a brew cycle is in progress and also that sufficient mineral deposits are present in the unit that cleaning is recommended. An insulated carafe is used as the vessel to receive brewed coffee thereby eliminating the need for a keep warm plate. The unit may be mounted under a cabinet to thereby maximize usable counter top space and a coffee basket for the unit utilizes a dispensing valve which is opened by the carafe when inserted into position but which closes when the carafe is withdrawn. A thermostat which is used in association with an electrically energizable hot water generator for the unit has a manual reset switch which is activated by a self contained water reservoir when moved from a withdrawn position into its operative position.

A water supply conduit is in communication with and extends between a brewing station and the water reservoir when the latter is in its operative position to enable the flow of water from the reservoir to the brewing station. The hot water generator heats the water in the supply conduit between the operative water reservoir and the brewing station to a sufficient extent as it flows to enable coffee to be brewed at the brewing station. Insertion of the carafe into its coffee receiving position initiates the brew cycle unless any one of a plurality of operating conditions are not implemented. Specifically, the brew cycle will not commence, or continue, in the event the water reservoir and coffee carafe are not in operating positions. This ability of the apparatus to purposefully fail to start or to interrupt a brew cycle unless all conditions are fulfilled eliminates possible damage to the apparatus, excessive waste of materials and energy, and avoids a soiled work area of the type which can occur in the event a carafe or other vessel for receiving the brewed coffee is not positioned to receive the coffee during the brew cycle. The unit will also indicate to the user if a brew is attempted when there is no water in the reservoir or if the heating chamber is heavily calcified.

Another benefit of the invention is a significant increase achieved of usable counter space by reason of the invention. Specifically, an insulated carafe is used which obviates the necessity for a warmer plate beneath the coffee receiving vessel. Accordingly, the countertop itself is completely free for use. In accordance with the present invention, the carafe, in its operative brewed coffee receiving position, is suspended from an upper rim. When not in use, the carafe can be removed, thereby further increasing the space between the countertop and the underside of the coffee brewing available for use for other purposes.

Also, the brewing system of the invention provides a drip stop for a coffee basket positioned at the brewing station. Specifically, the brewing basket incorporates a cam operated valve mechanism which is biased to a closed position to prevent flow of coffee from the brew basket. However, when the carafe is moved to its coffee receiving position, its lid engages the cam operated valve mechanism which causes it to open and permits the flow of brewed coffee into the carafe.

Still another benefit of the invention resides in its construction according to which insertion of the self contained water reservoir to its operating position serves to manually reset the thermostat associated with the hot water generator and positioned at the rear of the apparatus. The resetting operation is achieved without the use of complex linkages or with the requirement of a manually operated mechanism representing still an additional operation to be performed by the user.

Other and further features, objects, advantages, and benefits of the invention will become apparent from the following description taken in conjunction with the following drawings. It is to be understood that both the foregoing general description and the following detailed description are intended to be exemplary and explanatory but not restrictive of the invention. The accompanying drawings which are incorporated in and constitute a part of this invention, illustrate one embodiment of the invention, and together with the description, serve to explain the principles of the invention in general terms. Throughout the disclosure, like numerals refer to like parts.

FIG. 1 is a perspective view of an automatic coffee brewing system embodying the invention;

FIG. 2 is a detail side elevation view of the coffee brewing system illustrated in FIG. 1;

FIG. 3 is an enlarged side elevation view of the system illustrated in FIG. 2;

FIG. 4 is a front elevation view of the coffee brewing system illustrated in FIG. 1, certain parts being cut away and shown in section for purposes of clarity;

FIG. 5 is an exploded perspective view, taken from the rear of the coffee brewing system of the invention;

FIG. 6 is a rear elevation view of the coffee brewing system of the invention;

FIG. 7 is an end elevation view of the coffee brewing system of the invention, certain parts being cut away along line 7--7 in FIG. 6 and shown in section for purposes of clarity;

FIG. 8 is a top plan view of the coffee brewing system, certain parts being cut away for purposes of clarity;

FIGS. 9 and 10 are side elevation views, certain parts being cut away and illustrated in section, illustrating two positions of a coffee receiving carafe to show its interrelationship with a coffee basket utilized by the invention;

FIG. 11 is a detail bottom plan view of components illustrated in FIGS. 9 and 10;

FIGS. 12 and 13 are cross section views taken generally along line 12--12 in FIG. 6 and illustrating different respective positions of components illustrated in those figures;

FIG. 14 is an electrical schematic diagram which illustrates the manner of operation of the coffee brewing system of the invention; and

FIG. 15 is a front elevation view of the front face of the coffee brewing system of the invention with the escutcheon in place.

Turn now to the drawings and, initially, to FIGS. 1-4 which illustrate an automatic coffee brewing system 20 which embodies the present invention. The apparatus 20 includes a main housing unit 22 which contains all of the necessary elements for brewing coffee, specifically, a self contained water reservoir 24, a water heating and pumping system 26 (see FIGS. 5 and 6), and a brewing station 28 including a coffee basket 30.

The housing unit may be attached to the underside of a cabinet 32 or of any horizontal surface by means of an intermediate bracket 34 (FIG. 4) and secured with screws or other suitable mounting devices. In its mounted condition, especially as seen in FIG. 2, the housing unit 22 is of minimal height and provides a maximum of room above a countertop 36 and, especially, between the countertop and the cabinet 32. The lowest part of the housing unit 22 is located at its rearmost side adjacent a wall 38 and, therefore, substantially out of the way.

A vessel for receiving brewed coffee is preferably in the form of an insulated carafe 40 which is an independent part of the coffee brewing system 20. The carafe is provided with a rim 42 at its upper regions which is supportively and slidably received by a pair of opposed support tracks 44. By reason of this construction, the carafe does not require bottom support while in its operative position. It can, therefore, be much taller than traditional coffee receiving vessels intended to be positioned under a cabinet thereby improving the ease with which coffee can be poured from it. The relationship between the rim 42 and the support 44 also enables the carafe to be readily moved from a withdrawn position to an operative position as illustrated in FIGS. 1-4.

The water reservoir 24 is self contained and is generally in the form of an enclosed drawer which is slidably received on a shelf 46 of the housing unit 22. A plurality of spaced parallel runners 49 integral with the reservoir 24 and extending downwardly therefrom serve to improve the slidability of the reservoir on the shelf 46. Thus, the reservoir 24 can be withdrawn from the housing unit 22, filled from a faucet with an amount of water equivalent to the number of cups of coffee desired, then reinserted into the unit. Viewing especially FIGS. 5 and 7, when the reservoir 24 is in its operative position, an outlet valve 50 which is normally biased closed is engaged by a needle 52 mounted within a fitting 54 located at an extreme end of the water heating and pumping system 26. The water heating and pumper system 26 includes a water supply conduit 56 which is in communication with and extends between the fitting 54 and the brewing station 28. It includes a descending leg 58, a transverse leg 60, and an ascending leg 62.

The system 26 also includes an electrically energizable hot water generator 62 immediately adjacent the transverse leg 60 which operates in a known manner for heating of water in the supply conduit to a sufficient extent as it flows from the reservoir 24 to the brewing station 28 to enable coffee to be brewed at the brewing station. In the general operation of the system 20, in a known manner, water flows from the reservoir 24 through the descending leg 58, then across the transverse leg 60 where it is heated by the hot water generator 62. Thereafter, the resulting water and steam mixture rises through the ascending leg 64 to a shower plate 66 which overlies the coffee basket 30. Also in a known manner, a filter 68 of paper or other suitable material is positioned in the coffee basket 30 to receive fresh ground coffee 70. Hot water pumped by the generator 62 through the ascending leg 64 passes through a plurality of suitably positioned openings 72, 74 (see FIG. 8) in the shower plate 66 onto and through the ground coffee 70 and filter 68 for eventual reception by the carafe 40 when in its operating position.

With particular reference now to FIGS. 9 and 10, the coffee basket 30 is seen to include a side wall 76 and a bottom wall 78 for supporting the filter 68 and ground coffee 70 therein. The bottom wall 78 is provided with at least one centrally disposed discharge opening 80 and generally slopes downwardly from the sidewall to the discharge opening. A generally disc shaped, contoured, cam plate 82 underlies the bottom wall 78 and is substantially coextensive therewith. The cam plate 82 has a concave surface which faces the bottom wall and a convex surface which faces away from the bottom wall. A pin member 84 is fixed to the cam plate 82 and extends in a transverse direction away from a central region of the concave surface of the cam plate, then freely through the discharge opening 80 in the bottom wall 78. A deformable valve member 86 composed of rubber or other suitable material is fixed to the pin member distant from the cam plate 82.

A spider spring member 88 is interposed between the bottom wall 78 and the cam plate 82 and serves to bias the cam plate 82 away from the bottom wall 78. As seen in FIGS. 9-11, the spider spring member 88 includes a central ring 90 which is coaxially received over a circular rib 92 which protrudes outwardly from the bottom wall 78. A plurality of resilient legs 94 extend radially outwardly from the central ring 90 and also extend away from the bottom wall 78 when it assumes the relationship illustrated in FIGS. 9 and 10. The central ring 90 bears against the bottom wall 78 while the extremities of the legs 94 bear against the concave surface of the cam plate 82.

Thus, when the cam plate 82 is in its relaxed position as illustrated in FIG. 9, the valve member 86 engages a valve seat defined as the intersection within the coffee basket of the bottom wall 78 and the discharge opening 80. As a result, coffee is normally prevented from issuing from the coffee basket. However, when the carafe 40 is moved from its withdrawn position as seen in FIG. 9 to its operative position as illustrated in FIG. 10, an upper lid 96 of the carafe engages the cam plate 82, unseating the valve member 86 and allowing coffee to flow, by gravity, into the carafe. Subsequently, when the carafe 40 is withdrawn, as to the position illustrated in FIG. 9, the cam plate 82 returns to its relaxed position, the valve member again seals the discharge opening 80 and any liquid coffee remaining in the coffee basket 30 is prevented from dripping, undesirably, upon the countertop 36 or whatever else is located beneath the housing unit 22.

A plurality of pins 97, concentrically aligned with the rib 92, similarly extends away from the bottom wall 78. The cam plate 82 terminates at an upturned circular rim 82A which is concentric with and proximate to the pins 97. The circular rim and the pins are mutually cooperable to guide the cam plate 82 between the first and second positions, the pins being engageable with the cam plate and the circular rim being engageable with the extended surface of the bottom wall when the cam plate is in the valve unseating position.

In order to operate the hot water generator 62, it is necessary to actuate an associated manual reset thermostat switch 98. An improved actuating mechanism for this purpose will now be described with particular reference to FIGS. 5, 12, and 13. The thermostat, or temperature sensitive switch, 98 is commonly available from numerous sources, but one example of a switch suitable for purposes of the invention is Model No. 1NT08 manufactured by Texas Instruments, Inc. Being of a manual reset type, the switch 98 need only be pressed once, without the need of continuing to press the switch to maintain its actuation. An actuating mechanism 100 has been devised to accomplish this end result in combination with another operation which must also be performed.

The manner of moving the reservoir 24 from a withdrawn position to an operative position for connection to the water supply conduit 56 has previously been described. As the reservoir 24 is moved from its withdrawn position and toward its operative position, a downwardly extending tab 102 integral with the reservoir engages the actuating mechanism 100 in a manner to be described. A pair of parallel, spaced, support ears 104 are suitably mounted on a housing encompassing the transverse leg 60 and the hot water generator 62. A stub shaft 106 extends between and is supported by the ears 104, and, in turn, supports an arcuate shaped, resilient, rocker cam 108 which extends between an actuator member 110 at one end and a cam member 112 fixed to its opposite end.

As the reservoir 24 moves toward the left (FIG. 12) as it approaches its operative position, the tab 102 engages a first surface 114 of the cam member 112. With continued movement of the reservoir in the same direction, cam member 112 travels with it and causes the rocker cam 108 to rotate on the stubshaft 106 in a counterclockwise direction until the member 110 engages a button 118 of the switch 98 and thereby resets the switch. With continued leftward movement of the reservoir, the rocker cam 108 is caused to deform until the tab 102 overrides an extreme tip 120 of the cam 112. When the reservoir reaches its operative position as seen in FIG. 13, the rocker cam 108 returns to its normal, relaxed position disengaged from the button 118. Subsequently, when it is desired to withdraw the reservoir from the housing unit 22, it is moved to the right (FIG. 12) until it engages a surface 122 on an opposite side of the cam member 112. Continued rightward (FIGS. 12 and 13) movement of the reservoir 24 causes the rocker cam 108 to pivot in a clockwise direction around the stubshaft 106 until the tab 102 again overrides the extreme tip 120 and allows the rocker cam 108 to return to its normal position (FIG. 13).

However, the thermstat switch 98 is not the only switch with which the reservoir 24 is involved. At the same time that the reservoir 24 is moved to the rear of the housing unit 22 to join the valve 50 with the fitting 54, its rear wall is also caused to engage an actuating arm 124 of a limit switch 125 (see FIGS. 8 & 14) which is not actuated until the reservoir is at the extreme end of its travel with the valve 50 fully joined to the fitting 54. The reason for this construction is to assure that a brewing cycle will not commence until there is a firm, sealed, connection between the valve 50 and the fitting 54. Otherwise, it would be possible for a brew cycle to commence with leakage of water from the valve and fitting interface, the result being an incomplete brew.

With the aid of FIG. 14, especially, the operation of the automatic coffee brewing system 20 will now be described. A brew cycle is initiated when the carafe is inserted into its operating position so long as all other necessary operating conditions are implemented and, once the brew cycle has been initiated, it proceeds to its conclusion. However, in accordance with the invention, the brew cycle does not proceed in the event any one of those necessary operating conditions have not been implemented.

As illustrated in FIG. 14, the brewing system 20 is AC powered, connection to an electrical outlet being achieved in a customary manner by means of a plug 128. With reference now to FIGS. 1, 14, and 15, a face plate or escutcheon 132 is provided on the housing unit 22 and indicates a number of items of information concerning the status of operation of the brewing system. Specifically, it indicates whether a main power switch 134 has been actuated that is slidably movable from an "off" position to a "start" position. Also, by means of a lighted "brewing" lamp 136, the user is informed that a brew cycle is in progress and by means of a "clean" lamp 138, the user is informed that it has become desirable to perform a cleaning operation to remove the mineral deposits which have accumulated.

In actual use, following installation of the coffee brewing system 20 beneath the cabinet 32, the power switch 134 may be moved to the start position and thereafter retained in that position. Thus, initiation of a brew cycle can be achieved solely by insertion of the carafe 40 to its operating position so long as the other mentioned operating conditions have been implemented. The brew cycle is then performed to its conclusion resulting in an amount of brewed coffee within the carafe 40 consistent with the amount of water introduced to the water reservoir 24. In the even all of the operating conditions have been implemented and a brewing cycle is actually underway, the brewing lamp 144 (FIGS. 14 & 15) is lighted to indicate this fact. At the conclusion of the brew cycle, that is, when all of the water has left the water supply conduit 56, the brewing lamp 144 turns off.

The operating conditions which must be implemented in order for a brew cycle to proceed to its conclusion will now be discussed. First, with the power switch 134 already moved to the closed position, the water reservoir 24 must be in its operative position with the valve 50 matingly engaged with the fitting 54 to assure its connection to the water supply conduit 56. In this operative position, the tab 102 will already have actuated the reset button 118 of the thermostat switch 98 to thereby move the thermostat switch to its closed position. Also, the reservoir limit switch 125 will have been moved to its closed position. However, not only must the reservoir 24 be in its operative position, but it must also contain a sufficient amount of water for a meaningful brew cycle to commence. Therefore, if in fact, the reservoir is in its operative position but the user forgets to fill it partially or completely with water, the brew cycle will begin, but the thermostat switch 98 will be caused to open after a short passage of time as, for example, 40 seconds, or, in any event in less than one minute. That is, since no water will be flowing through the transverse leg 60, it will become heated to a temperature at which the thermostat switch 98 opens to inactivate the system. Next, the carafe 40 must be in the operative position (FIGS. 1-3) engaged with a button 150 (see especially FIGS. 5 and 10) slidably received on the housing unit 22 for selective engagement with an arm 152 of a microswitch 154.

Also, it will be appreciated that, for purposes of safety, the brewing system 20 includes a primary fuse 156 and a secondary fuse 158 which are electrically in series between the power source, as represented by the plug 128, and the hot water generator 62. It is desirable that the fuses 156, 158 be of staggered rupture values within the range of safety to preclude the possibility that both fuses might originate from the same bad lot.

Another helpful indication provided by the coffee brewing system 20, as previously noted, is that it is time to clean the water supply conduit of substantial accumulated mineral deposits. Such a condition is indicated by the "clean" lamp 138. The lamp 138 becomes lighted only after the thermostat switch 98 opens and in response to the operation of a sensing mechanism 160. The sensing mechanism 160 operates on the principal that the presence of water in the supply conduit 56 upstream of the hot water generator 62 after the thermostat switch 98 opens is indicative of the presence of substantial mineral deposits located primarily in the transverse leg 60 which thereby prevents all the water initially in the reservoir 24 from being received at the brewing station 28 prior to completion of the brew cycle. When water is present in the supply conduit 56 upstream of the hot water generator 62 after the thermostat 98 opens, a water sensor switch 162 (FIG. 14) which is a component of the sensing mechanism 160 is caused to open, thereby lighting the clean lamp 138.

The clean lamp 138, then, serves to notify the user that the water supply conduit 56 needs cleaning in the known manner, but still permits a brew cycle to continue to its conclusion. In the extreme instance in which the water supply conduit 56 will no longer permit the flow of water because of a totally calcified condition, the thermostat switch 98 would be caused to open because of the excessive heat generated in the absence of the cooling effect of water flowing through the supply conduit 56. The sensing mechanism 160 may be of the novel construction disclosed in commonly assigned U.S. patent application Ser. No. 216,706, filed July 6, 1988, now U.S. Pat. No. 4,327,837, of Paul D. Johnson et al entitled "Calcification Indicator" and filed concurrently with the instant application. The aforesaid application is hereby fully incorporated into this application, by reference.

When it becomes necessary or desirable to turn off the brewing system 20, all that needs to be done is to remove the carafe 40 to a withdrawn position. The valve member 86 will assure that any residue of brewed coffee in the coffee basket will remain contained until the carafe is returned to its operative position. This end can also be achieved by moving the reservoir 24 to a withdrawn position or by moving the power switch 134 to the "off" position.

Although a preferred embodiment of the invention has been disclosed in detail, it should be understood by those skilled in the art that various modifications may be made to the illustrated embodiment without departing from the scope as described in the specification and defined in the appended claims.