Patent Application
20120017765
The present invention relates to coffee makers and in particular to drip-type coffee makers. The invention also relates to coffee bean grinders.
One method of making coffee includes passing heated water through coffee grounds in order to infuse the water with coffee flavor and aroma. A common type of coffee maker that employs this method is the so-called “drip-type” or “filter” coffee maker. Filter coffee makers comprise a water reservoir and a brew basket for receiving coffee grounds. A delivery tube or other water passage takes water from the water reservoir, through an in-line water heater, and delivers it to a spreader above coffee grounds in the brew basket. The heated water passes through the coffee grounds and in to a carafe, cup or other vessel.
The art to making good coffee relies not only on the correct water temperature and wetting time, but also on the quantity of water and grind coffee used in preparing the brew. Opinions vary widely but organizations such as the National Coffee Service Association recommend a ratio of approximately 11 grams of coffee to 8 fluid ounces of water.
One of the problems with known coffee makers, and in particular domestic or home use coffee makers, is the need to constantly measuring out exact quantities of water and coffee when making a brew. It is often the case that the number of cups, or quantity of coffee, may varies from brew to brew. Thus, there is a need to constantly adjust measurements and to work out exact quantities for each brew. One solution practiced by many users of domestic or home coffee makers is to measure out a known fixed quantity of coffee and water for each brew. For example a user may place three scoops of coffee in the brew basket for one full load of water. This can result in coffee wastage or in more extreme cases a shortage of coffee requiring a second brew which may only be partly consumed. As a result many users resort to rule of thumb guides such as “one scoop per cup plus one for the pot”. Such methods are imprecise often resulting in variable brew quality which detracts from the coffee drinking experience.
It is an object of the present invention to overcome, or at least eliminate, the above-mentioned problem with known coffee makers, in particular domestic or home use coffee makers, by providing a coffee maker and a method of operating coffee maker which may be used to produce a consistent strengthen and flavor of coffee from brew to brew regardless of whether a small or large number of cups is being prepared. It is a further or alternative object of the invention to provide a coffee bean grinder.
There is disclosed herein a coffee maker and coffee bean grinder that have a bean hopper for storing coffee beans, a bean grinder for grinding coffee beans into coffee grounds and a bean delivery device for delivering a quantity of beans from the bean hopper to the grinder. The bean delivery device has a bean receptacle and is movable between first and second positions. In the first position the bean receptacle communicates with the bean hopper and in the second position the bean receptacle communicates with grinder. A controller controls movement of the bean delivery device between the first and second positions.
The bean delivery device can be a wheel for rotational movement between the first and second positions. In a preferred embodiment first and second positions are offset 180 degrees with respect to each other, but other offsets are possible. Where a 180 degree offset is used the wheel has a second bean receptacle offset 180 degrees with respect to the other bean receptacle. In other embodiments the bean delivery device can be a reciprocating member movable between the first and second positions
The bean receptacle(s) have a first opening in a first side of the wheel for communicating with the bean hopper to receive beans within the receptacle(s), and a second opening in a second side of the wheel for communicating with the grinder.
Preferably two motors are provided. A first motor operates the grinder and a second motor for operates the bean delivery device so that the delivery device and grinder blades can be operated independently.
A coffee maker also has a water reservoir and a water level sensor located in the water reservoir. The controller can be configured to control movement of the bean delivery device based on the signal from the water level sensor. There can also be a user input having two or more user selectable preference. The controller is in communication with the user input and can alternatively control movement of the bean delivery device based on the signal from the water level sensor and/or a second signal from the user input.
Further aspects of the invention will become apparent from the following description, which is given by way of example only.
Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings in which:
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.
Referring to
Located on the top of the head portion (5) is a bean hopper (9) having an opening (10) at its lowermost point. The bean hopper (9) can be arranged to hold whole coffee beans or to accept a coffee bean container such that, in either case, coffee beans can pass through the opening (10) in the lower part of the hopper (9). Located within the head (5) of the coffee maker is a coffee bean grinder (21) which communicates with both the opening (10) in the bean hopper and with the brew basket (6). The coffee bean grinder (21) is of a type known in the art and is operated by an electric motor (22). When the motor (22) is energized the grinder (21) operates drawing beans from the bean hopper (9) through opening (10) grinding the beans into coffee grounds which fall into the brew basket (6).
Referring specifically to
In
The coffee maker according to the invention overcomes problems with prior art coffee makers by an operating method which provides control quantity the amount of ground coffee in the brew basket (6) based upon the selected coffee strengthen—weak, mild or strong input by selector switch (15)—and/or the amount of water in the water reservoir (2). In the most basic embodiment of the invention the coffee maker is operated by the microprocessor (23) such that a fixed volume of coffee beans is deposited in the brew basket (6) based upon the setting of the strength select switch (15). For a mild brew the controller (23) operates the coffee grinder motor (22) for less time so that a minimum amount of coffee grounds are deposited in the brew basket (6). For a medium brew the controller (23) operates the grinding motor (22) for an average amount of time putting an average, or medium, amount of coffee grounds in the brew basket (6). For a strong brew the controller (23) operates the grinding motor (22) for a longer period of time at a deposit a greater amount of coffee beans in the brew basket (6). The microcontroller (23) uses the float switch in order to determine the level of water in the water reservoir (2) and indicates the water level on the water level indicator (18) viewable by the user. In this way the user can accurately fill the water reservoir (2) to a desired level based on experience. This makes it much simpler for a user to gauge the correct quantities of coffee and water for different brews and to obtain more consistent strength and flavour of coffee from consecutive brew cycles.
In an alternative, and preferred, embodiment of the invention the microcontroller operates the grinding motor (22) for different lengths of time based on both the brew strength selected via the brew selector switch (15) and on the water level within the reservoir (2). Thus, the length of time that the microprocessor (23) operates the grinding motor (22) is based not only on the strength selected but on the water level. So, for example, if a weak brew is selected and the water reservoir is full more coffee grounds are needed than if a weak brew is selected and the reservoir is half full (or half empty). A look-up or mapping table can be used by the microcontroller (23) in order to determine the amount of coffee grounds needed depending on the water level in the water reservoir (2). The water level in the water reservoir (2) can be determined by a separate mapping table mapping the resistance value of the variable resistor (20) to the water level in the reservoir (2) as previously discussed. A third mapping table can be used to map the length of time that the coffee grinding motor (22) must be operated for depositing a certain amount of coffee grounds into the brew basket (6). Alternatively, a single mapping table can be used to map a resistance value of the variable resistor (20) and a brew strength setting of the selector switch (15) to a grinding motor (22) operating time. Such arrangements of mapping tables are common in the microprocessor programming art and well within the capability of a skilled addressee. The various quantities need for a quality brew of coffee are well-known, but essential to the invention. One typical value quoted is 11 grams of grounds to 8 ounces of water.
At step 4 the microprocessor displays (23) the water level within the reservoir (2) on the water level indicator (18). At step 5 the microprocessor checks a selected coffee strength set at coffee strength selector switch (15). At step 6 the microprocessor (23) calculates the preferred/needed operating time of the grinding motor (22) based on the coffee strength selection and the water level as previously described. At step 7 the microprocessor (20) operates the grinding motor (22) for the determined operating time and after the required time turns-off the grinding motor (22). At step 8 the microprocessor (23) operates the in-line water heater (3) to heat water in the water reservoir (2) and deliver it to the brew basket (6). The microprocessor (23) continues to operate the water heater (3) until all the water in the reservoir (2) is used up. This can be determined via the water level float switch. A safety thermostat to shut-off the water heater (3) should the reservoir (2) run dry can also be included. After the water heater (3) is switched off the coffee is ready to serve.
The bean delivery wheel (29) comprises a circular wheel having a toothed outer periphery (31) and two diametrically opposed arcuate shaped receptacles (32, 33). The receptacles (32, 33) have openings (41, 42) at both ends in the form arcuate apertures through the delivery wheel (29). The delivery wheel (29) is positioned on a rotational axis (38) located equidistant between outlet (30) of hopper (9) and the opening (40) in the top of grinder inlet chute (28). The arrangement is such that when the delivery wheel (29) is rotationally positioned in one of two positions, one of which is 180 degrees offset from the other, the outlet (30) of the bean hopper (9) is aligned with the upper opening (41) of one arcuate receptacle, for example receptacle (33) as illustrated in
The receptacles hold a measured quantity of coffee beans, which is made known to the controller either by programming the quantity into the controller or by storing the quantity in non-volatile electronic memory accessible by the controller. The controller (23) can operate delivery wheel (29) and so control the quantity of coffee beans delivered to the grinder (26) and thus the amount of coffee grounds in brew basket (6). The controller (23) can control the number of full rotations or half rotations of the delivery wheel (29) based on input from the input selective switch (15) and/or the amount of water in the water reservoir (2) as previously described in order to control the amount of grounds in the brew basket and thus the strength of the brew. The grinder motor (22) is operated continuously to grind all beans delivered to the grinder (26).
Although the receptacles (32, 33) are accurate in the referred example this is not essential to the invention and they could be any suitable shape adapted to the shape of outlet (30) of hopper (9) or the inlet (40) of the grinder inlet chute (28). Further, while in the described embodiment the delivery wheel (29) has two receptacles (32,33) and turns 180-degrees for movement of the receptacles between the hopper outlet (30) and grinder inlet chute (28), it will be apparent to a person skilled in the art that the delivery wheel may have just one receptacle or may have more than two receptacles, and that the hopper outlet and grinder inlet chute may be less than 180 rotational degrees of the wheel apart. For example, the hopper outlet and grinder inlet chute maybe only slightly misaligned with the wheel on an offset axis such that it turns a small number of degrees to align a receptacle between the hopper outlet and grinder inlet chute. In one such embodiment the delivery wheel has four receptacles spaced 90-degrees apart and turns 90-degrees to move one receptacle between the hopper outlet and grinder inlet chute. A full 360-degree rotation results in each receptacle being sequentially aligned with the hopper outlet and then the grinder inlet chute to deliver four “loads” of coffee beans to the grinder.
Thus, according to the invention there is a coffee maker and a method of operating a coffee maker which can repeatedly produce a consistent strength and flavour coffee brew regardless of the number of cups or the varying tastes of the user.
A coffee bean delivery system for delivering a measured quantity of coffee beans from a bean hopper to a bean grinder is described as practiced in a coffee maker. Separate coffee grinders are also. The bean delivery system can also be practiced in a coffee grinder. In a preferred embodiment such a coffee grinder includes a bean hopper for storing coffee beans, a bean grinder for grinding coffee beans into coffee grounds, and a bean delivery device for delivering a quantity of beans from the bean hopper to the grinder. The bean delivery device has bean receptacles and is movable between first and second positions in which the bean receptacles communicate with the bean hopper and grinder respectively. Coffee grounds are collected in a vessel for transfer to a storage container or directly to the brew basket of a coffee maker. The grinder preferably has two motors. A first motor operates the grinder blades and a second motor operates the bean delivery device so that the delivery device and grinder blades are separately operable. A controller in the grinder controls the motors. A user input on the grinder is provided for allowing a user to select a quantity of beans to grind. The controller determines the number of operations of the bean delivery device to achieve the selected quantity.
In the above-described embodiment various preferred examples are given. It must be appreciated that improvements and/or modifications obvious to those skilled in the art are not excluded from the scope of the present invention. For example, in the description a float-type water level detection means is included. Various other mechanical or electronic water level detectors and sensors are known in the art and should be considered within the scope of the present invention.
