A device for brewing espresso coffee

Abstract

There is provided a device for brewing espresso coffee, the device having: a cylinder defining a cavity for receiving liquid; a plunger axially slidable within the cavity between an inserted position and a retracted position; and an actuator having a biasing member for biasing the plunger towards the inserted position, the actuator adapted to change the configuration of the device from a rest configuration to an actuated configuration, and in the rest configuration the plunger is in the inserted position and the biasing member exerts a minimum biasing force on the plunger, and in the actuated configuration the plunger is in the retracted position and the biasing member exerts a maximum biasing force on the plunger.

Description

[Technical Field]

[0001] Field The present disclosure relates to machines for brewing espresso coffee, and more particularly to machines for manually brewing espresso coffee. [Background technology]

[0002] background Coffee is one of the most widely consumed beverages in the world. It is typically consumed hot and is prepared by extracting soluble components from ground coffee (i.e., the granular powder formed by grinding roasted coffee beans) using hot water. It is well known that the taste of coffee, even starting from the same ground coffee, can vary significantly depending on the precise conditions under which the extraction is carried out. One known and widely used method is to pass a relatively small amount of hot water under relatively high pressure through a compressed block of coffee powder, forcing the water through the block. This results in a certain amount of espresso coffee, which is a type of coffee beverage preferred by many users, or is the primary component of such a beverage.

[0003] For example, to produce espresso coffee in a cafe or restaurant, it is common to use a countertop "espresso machine." These machines generally include a plumbed water supply and a means for maintaining a reservoir of water at a relatively high temperature, as well as a complex system for discharging a metered amount of such water through a block of compressed ground coffee, which is held tightly against the machine's pressurized water outlet by a cylindrical metal pot within which the block of ground coffee is compressed.

[0004] The compressed block of ground coffee may be loose coffee granules placed in a pot (traditionally, the pot is filled to the brim, and then the granules are compressed to a smaller volume before or when the pot is installed in the machine), or it may be in the form of a pouch or "pod" made of a water-permeable material and sized to fit snugly within the pot. The pot is provided with means for holding itself tightly sealed against the pressurized water outlet. Traditionally, this is achieved by a protrusion on the outside of the pot engaging a short threaded section on the inside of a skirt surrounding the outlet. The pot usually has a laterally extending external handle that can be turned approximately 90° to screw the pot tightly into place. The base of the pot contains an aperture through which brewed coffee may fall during dispensing into a cup placed below the pot; the aperture may bifurcate to divide the effluent into two streams, one for each of the two streams, one for each of the two streams.

[0005] Such devices provided for use in cafes and restaurants are of considerable size and usually require plumbing to a water system, and are therefore not ideally suited for home use. Scaled-down versions of such commercial espresso machines have been manufactured for home use for many years, but such devices have traditionally required an electrical supply.

[0006] However, home espresso machines of this nature have many drawbacks. For example, they often have a small reservoir that is inconveniently but necessarily located at the rear of the machine. Furthermore, home espresso machines often have a relatively small and weak pump for forcing water through a compressed block of coffee powder, meaning that the pump either quickly wears out in an attempt to achieve the pressure required to extract espresso coffee, or the required pressure is never achieved, resulting in a deterioration in the quality of the extracted coffee. Furthermore, home espresso machines are often still bulky, taking up a significant amount of space in the home kitchen, and require a mains power source to function, meaning that the machine is not portable and is not capable of extracting espresso coffee outside of a home environment.

[0007] Some examples of espresso machines exist that utilize a single lever pulled by the user to force a certain amount of water through a compressed block of ground coffee. Often, these machines still require mains power and / or plumbing to provide heated water for brewing the coffee. Furthermore, the single-lever arrangement of these machines is typically cumbersome, requires a significant amount of strength from the user to achieve the necessary force, and requires the user to remain engaged with the machine throughout the entire brewing process.

[0008] An example of a machine for brewing espresso coffee is illustrated in EP 1509112, which discloses a lever-operated device for driving water through coffee grounds using a plunger to extract espresso coffee. In this case, the user must provide all of the downward force to drive the plunger and force the water through the coffee grounds. This requires a significant amount of strength from the user to achieve the force necessary to extract espresso coffee, and the user must remain engaged with the machine throughout the entire extraction process.

[0009] The present disclosure has been conceived in light of the above considerations. Summary of the Invention

[0010] overview In a first aspect, there is provided an apparatus for brewing espresso coffee, the apparatus comprising: having a cylinder defining a cavity for receiving a liquid; a plunger axially slidable within the cavity between an inserted position and a retracted position; and an actuator having a biasing member for biasing the plunger toward the insertion position; The actuator is adapted to change the configuration of the device from a rest configuration in which the plunger is in an inserted position and the biasing member exerts a minimum biasing force on the plunger, to an actuated configuration in which the plunger is in a retracted position and the biasing member exerts a maximum biasing force on the plunger.

[0011] This provides a means for brewing espresso coffee in a semi-automatic manner without requiring an electrical power source. To extract coffee, the user need only use the actuator to change the configuration of the device from its rest configuration to its actuated configuration, which retracts the plunger and causes the biasing member to increase the biasing force exerted on the plunger. The biasing member automatically drives the plunger toward its inserted position, thereby forcing liquid from the cavity through, for example, a quantity of ground coffee, forcing the liquid out of the cavity, and the device returns to the rest configuration.

[0012] Because the biasing member, rather than the user, drives the plunger to its inserted position within the cavity, the user does not need to exert force to move the plunger the full distance between its retracted and inserted positions to complete the brewing process. Rather, once the user uses the actuator to change the device to the operating configuration, the device automatically completes brewing an espresso coffee without requiring further input from the user. Thus, the device significantly reduces the amount of time a user needs to interact with a manual coffee maker to obtain an espresso coffee. Furthermore, the provision of a biasing member reduces the effort required by the user to return the plunger to its inserted position within the cavity and complete the brewing process.

[0013] The device includes an actuator for changing the configuration of the device from a resting configuration to an actuated configuration, the actuator being configured to slide the plunger from an inserted position to a retracted position and for imparting potential energy to the biasing member.

[0014] The actuator may have an actuating element. The actuating element may be movable to change the configuration of the device from a resting configuration to an actuated configuration. The actuating element may be movable in a first motion and a second motion opposite to the first motion. The actuating element may change the configuration of the device from the resting configuration to the actuated configuration through a combination of the first motion and the second motion.

[0015] The actuation element may be a pivotable element (e.g., a lever) such that the first movement is a first pivotal movement and the second movement is a second pivotal movement, the first and second pivotal movements being in opposite rotational directions about the pivot.

[0016] In the first movement, the pivotable element may move from a first position lying against the cylinder to a second position raised away from the cylinder. In the second position, the pivotable element may move from the second position back to the first position. The pivotable element may rotate through an angle of approximately 180 degrees between its first and second positions.

[0017] The use of a pivotable element such as a lever provides the user with leverage when performing the first and second movements of the actuator, meaning that the user needs to apply less force to perform the movements and impart potential energy to the biasing member, thereby improving the ease of use of the device.

[0018] The at least one pivotable element may be pivotally connected to the cylinder. For example, the cylinder may have a flange to which the at least one pivotable element is pivotally connected. The pivotable element may be pivotally connected to the cylinder by a pin joint. The flange may be disposed adjacent to an open top of the cylinder, the open top being for receiving the plunger.

[0019] The actuator may further comprise a compression plate and a substrate, with the biasing member provided therebetween, such that the biasing member is sandwiched between the compression plate and the substrate.

[0020] In the rest configuration, the compression plate and the substrate may have a maximum spacing therebetween, and in the actuated configuration, the compression plate and the substrate may have a minimum spacing therebetween, so that the biasing member may be in a state of minimum compression between the compression plate and the substrate in the rest configuration, and in the actuated configuration, the biasing member may be in a state of maximum compression between the compression plate and the substrate.

[0021] The substrate may be directly or indirectly connected to the plunger (e.g., to a flange surrounding the shaft of the plunger). The connector to the plunger / flange may be at or proximal to the upper axial end of the plunger (i.e., the axial end not received in the cavity). Thus, movement of the plunger results in movement of the substrate. Correspondingly, movement of the substrate results in movement of the plunger.

[0022] The orientation of the substrate may be changed relative to the plunger during changes between configurations of the device.

[0023] In the actuated configuration, the compression plate is fixed relative to the cylinder and the base plate may be movable relative to the cylinder (but fixed relative to the plunger). The base plate may thus be movable by a biasing force provided by a biasing member such that a biasing force may be applied through the base plate to the plunger to drive the plunger towards its insertion position and return the device to the rest configuration.

[0024] The substrate may be a substantially circular plate or an annular plate.

[0025] The compression plate may be connected to an actuation element of the actuator, such that movement of the actuation element results in movement of the compression plate, and at least a second movement of the actuation element results in movement of the compression plate toward the substrate.

[0026] The orientation of the compression plate may be changed relative to the actuating element during such movement. The compression plate may directly abut the biasing member to subdivide the compression force on the biasing member as the device changes from the rest configuration to the actuated configuration.

[0027] The compression plate may be a substantially circular plate or an annular plate.

[0028] The biasing member may be any member capable of storing and releasing potential energy. The biasing member may have a compressible element that may be compressed by a compression plate approaching the substrate when the device is changed from the actuated configuration to the resting configuration to impart potential energy to the biasing member.

[0029] The compressible element may comprise a spring. The spring may be pre-tensioned. By providing a pre-tensioned spring as the biasing member, a potential drop in force exerted by the biasing member as the plunger approaches its insertion position in the cavity and the device returns to its rest configuration is reduced or eliminated. In this way, a potential drop in pressure towards the end of the brewing process is reduced or eliminated, thereby improving the quality of the resulting coffee. Therefore, the minimum biasing force need not be zero.

[0030] The biasing member (e.g., a compressible element such as a spring) may have an upper end that abuts the compression plate and a lower end that abuts the substrate, and the biasing member biases the compression plate and the substrate separately.

[0031] The axial distance between the compression plate and the substrate is variable to effect compression of the biasing member while the device is transitioning from its resting configuration to its actuated configuration. For example, while the device is transitioning to its actuated configuration, the compression plate is forced toward the substrate, compressing the biasing member. After compression of the biasing member, the compression plate and the substrate are at their minimum spacing, and the biasing member is at its maximum compression state, thus exerting a maximum biasing force on the substrate (whose position is movable relative to the cylinder in the actuated configuration). Elasticity in the biasing member then drives the substrate away from the compression plate. The substrate is connected (directly or indirectly) to the plunger, so that as the substrate is forced away from the compression plate, the plunger is forced into the cavity toward its insertion position.

[0032] The actuator may further include an arm having a first lateral end pivotally connected to the actuation element and a second lateral end connected to the compression plate. The pivotable connection between the actuation element and the arm provides for movement of the arm relative to the actuation element as the device transitions to its actuated configuration, which may be accomplished by movement of the actuation element. For example, the arm may move from a vertical orientation substantially aligned with the axis of the cavity to an inclined orientation and back to the vertical orientation as the device transitions from the rest configuration to the actuated configuration. The compression plate may be fixedly or pivotally coupled to the arm. The compression plate may lie in a plane substantially perpendicular to the axis of the arm, at least in the actuated configuration of the device.

[0033] In some embodiments, the substrate may form the base of a housing, e.g., a cylindrical housing, a housing compression plate, or a biasing member. The substrate may be annular and may have an opening through which the arm passes. The biasing member may surround the arm within the housing. The compression plate is axially slidable within the housing and compresses the biasing member within the housing against the substrate. The axial end of the housing opposite the substrate is pivotally connected to the plunger. In this way, the substrate is indirectly connected to the plunger. In these embodiments, the compression plate is preferably a circular disk, which may be solid.

[0034] The housing may be pivotally connected to a flange surrounding the plunger (i.e., a flange surrounding the shaft of the plunger). The flange may be axially opposed to a head of the plunger, the plunger head being provided at the axial end of the plunger shaft that is received in the cavity.

[0035] Preferably, in these embodiments, there are two biasing members (e.g., compression elements, such as springs), each associated with a respective actuation element, arm, compression plate, base, and housing. Thus, a pair of pivotable actuation elements (e.g., a pair of levers) may be present. The pair of pivotable elements may be located on opposite sides of the device. For example, they may be substantially diametrically opposed, i.e., separated by an angle of about 180° around the central axis of the cavity, which is the same axis along which the plunger slides from the retracted position to the inserted position. The use of a pair of opposing pivotable elements means that the user needs to apply less force to each pivotable element to change the configuration of the device from the resting configuration to the actuated configuration. This may improve the ease of use of the device.

[0036] In other embodiments, there may be only a single biasing member, and the biasing member may surround the plunger shaft. In these embodiments, the substrate may be annular and may surround the plunger shaft (e.g., proximal to the plunger head). Thus, both the biasing member and the substrate are housed within the cylinder cavity. They may be axially slidable within the cavity. The substrate in these embodiments is fixedly connected to the plunger, and thus, after compression of the biasing member (when the device is in the actuated configuration), the substrate is forced away from the compression plate, thus driving the plunger further into the cavity into its insertion position. In these embodiments, the compression plate is annular and surrounds the plunger shaft. The compression plate may be pivotally connected to the arm.

[0037] The annular compression plate is axially slidable on the plunger shaft. For example, when the device transitions between the rest position and the actuated position, the compression plate is forced toward the top opening of the cylinder and the base plate, minimizing the spacing between the base plate and the compression plate (thus compressing the biasing element). When the device is in the actuated configuration, the compression plate may abut the top opening of the cylinder, such that the biasing element is entirely within the cylinder cavity (between the plunger shaft and the cylinder inner wall).

[0038] In these embodiments, the biasing member, substrate and compression plate may be associated with two pivotable elements and arms (e.g., two diametrically opposed pivotable elements / arms), with the pivotable elements each connected to the cylinder and the arms each connected between the respective pivotable element and compression plate, i.e., the two arms may be connected to opposite (e.g., diametrically opposed) sides of the compression plate.

[0039] In other embodiments, the biasing member may take the form of a pneumatic or hydraulic system.

[0040] The device includes a plunger axially received in the cavity (through the open top of the cylinder) for receiving the liquid, the plunger being axially slidable within the cavity by movement of the actuator and under the biasing force of the biasing member.

[0041] The plunger may include a plunger shaft and a plunger head, as described above, which provides a pressure surface facing the cavity to force the liquid out the bottom opening of the cylinder.

[0042] The plunger shaft may comprise a hollow tube. The tubular plunger shaft may have the same diameter as the plunger head.

[0043] The plunger head may have a cross-sectional shape similar to that of the cavity, such as circular.

[0044] The plunger may include a one-way valve mechanism to allow liquid to pass around the plunger head in only one direction. For example, it may include a one-way valve to allow liquid to pass from above the plunger head to below the plunger head (i.e., between the pressure surface and the bottom opening of the cylinder) as the plunger moves from the inserted position to the retracted position. Thus, a user may provide liquid to the cavity when the plunger is in the inserted position, and when a first movement of the actuator is performed and the plunger slides axially from the inserted position to the retracted position, the liquid passes from above the plunger head to below the plunger head. When the plunger is driven from the retracted position to the inserted position, the one-way valve prevents the liquid from passing through the plunger head and forces it through the coffee powder under pressure. The one-way valve may be implemented by an O-ring arrangement. The O-ring arrangement may include an O-ring located between the head of the plunger and the inner wall of the cavity, such that the O-ring rolls between an open position in which the liquid flow path in the plunger head is open and a closed position in which the liquid flow path in the plunger head is closed. The one-way valve mechanism may be as described in EP 1509112, which is incorporated herein by reference.

[0045] The device may further include a receptacle adjacent the base of the cylinder (i.e., below the bottom opening of the cylinder) for placing a quantity of ground coffee. The receptacle may also be adapted to receive and utilize a pre-packaged container holding a predetermined coffee brew mixture for brewing coffee. The receptacle may have one or more holes in its base that allow water, but not coffee powder, to pass through.

[0046] The receptacle for placing a quantity of ground coffee adjacent to the base of the cylinder may have a restrictor for restricting the flow of liquid from the cavity through the quantity of ground coffee, which is actuated by moving the plunger from a retracted position toward its insertion position within the cavity. The restrictor may be a plate having a through-hole for liquid passage. The through-hole may be between 0.3 mm and 0.6 mm in diameter, for example, 0.4 mm or 0.5 mm in diameter. The restrictor may be integrated into a portion of the receptacle for placing the ground coffee adjacent to the base of the cylinder. In this way, the pressure required to extract espresso may be achieved without depending on the size of the coffee powder provided to the device by the user. The relationship between the biasing member and the restrictor, for example, the relationship between the spring tension and the amount of restriction applied to the water flow, may be balanced to optimize the coffee extraction speed. For example, the relationship between at least one biasing member and the restrictor may be controlled to achieve an extraction time of between 25 and 30 seconds.

[0047] The apparatus may further include a stand connected to the cylinder. The stand may define a space therein for receiving a receptacle (e.g., a cup or glass) for receiving the coffee. The stand may further have a platform on which the receptacle for receiving the coffee may rest. The platform may have an outer rim for containing spills. The platform may have a series of raised formations for holding the receptacle for receiving the coffee away from spills.

[0048] The device may further include a pressure gauge. The pressure gauge may be provided to measure the pressure in the cavity. For example, the pressure gauge may be provided to measure the pressure in the cavity when the plunger is driven from the retracted position to the inserted position. The measured pressure may be provided to the user by any suitable display means so that the user can more accurately monitor the extraction of the coffee. The pressure gauge may include a pressure sensor and a display. The pressure sensor and the display may be integrated into a single element or may be provided as separate elements. The display may be a digital display or an analog display.

[0049] In a second aspect, there is provided a method for brewing espresso coffee using a device for brewing espresso coffee according to any one of the preceding claims, the method comprising: providing a quantity of liquid into a cavity of the device in a rest configuration; actuating the device using an actuator to change the configuration of the device to an actuated configuration; and driving the plunger towards its inserted position with the biasing force of the biasing member, thereby passing the liquid through a quantity of ground coffee.

[0050] The method may include placing a quantity of ground coffee adjacent a base of a cylinder of the device, the cylinder defining a cavity in which the liquid is received. The quantity of ground coffee may be placed adjacent the base of the cylinder using the receptacle described above.

[0051] When the device is in the resting configuration, a quantity of liquid is received in the cavity of the device. In the resting configuration, the plunger is in the inserted position, and the biasing member of the actuator of the device exerts a minimal biasing force on the plunger. The liquid received by the cavity may be water heated up to 100°C (e.g., water heated to 90°C-96°C), or any liquid suitable for extracting espresso coffee. When the liquid received by the cavity is heated water, the heating of the water may be performed external to the device, for example, by a kettle, a heated tap, or any other means for heating a quantity of water. Thus, the device does not require any plumbing connections for receiving the water or electrical means for heating the water itself.

[0052] The configuration of the device is then changed from the resting configuration to the actuated configuration using the actuator. In the actuated configuration, the plunger is in the retracted position and the biasing member is exerting a maximum biasing force on the plunger. The plunger head may include a one-way valve mechanism, as described above, for allowing liquid to pass from above to below the plunger head as the plunger moves from the inserted position to the retracted position. Thus, as the configuration of the device is changed from the resting configuration to the actuated configuration and the plunger slides from the inserted position to the retracted position, liquid provided to the cavity passes from above to below the plunger head.

[0053] The biasing member biases the plunger toward the insertion position, which causes the plunger to move toward its insertion position within the cavity when the device is changed to the actuated configuration. In the actuated configuration, the biasing member and plunger are the only elements that are not in their rest state and therefore the only elements that can move to release the potential energy held in the biasing member in the actuated configuration.

[0054] The plunger is thus driven towards its insertion position in the cavity and the liquid held below the plunger in said cavity is forced under pressure through a quantity of ground coffee.

[0055] The proposed apparatus includes combinations of the described aspects and preferred features, except where such combinations are clearly not permitted or are explicitly avoided. [Brief explanation of the drawings]

[0056] Drawing Overview Embodiments and experiments illustrating the principles of the present disclosure will now be described with reference to the accompanying drawings, in which:

[0057] [Figure 1] FIG. 1 shows an example of the present apparatus for brewing espresso coffee according to an embodiment of the present disclosure in a static configuration. [Figure 2] FIG. 2 shows the apparatus of FIG. 1 during transition of the apparatus from a rest configuration to an actuated configuration. [Figure 3] FIG. 3 shows the device of FIG. 1 in an operational configuration. [Figure 4] FIG. 4 is a perspective view of the device of FIG. [Figure 5A] FIG. 5A shows an example of a plunger head that may be utilized with the device as the plunger slides from an inserted position to a retracted position. [Figure 5B] FIG. 5B shows an example of a plunger head that may be utilized with the device as the plunger slides from the retracted position to the inserted position. [Figure 6] FIG. 6 shows an example of an apparatus for brewing espresso coffee according to a further embodiment of the present disclosure, the apparatus being in transition from a rest configuration to an operating configuration. [Figure 7] FIG. 7 shows the device of FIG. 6 in an operational configuration. DETAILED DESCRIPTION OF THE INVENTION

[0058] Detailed Description Aspects and embodiments of the present disclosure will now be described with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned herein are incorporated by reference.

[0059] There is provided a device for brewing espresso coffee, the device having: a cylinder defining a cavity for receiving liquid; a plunger axially slidable within the cavity between an inserted position and a retracted position; and an actuator having a biasing member for biasing the plunger towards the inserted position, the actuator adapted to change the configuration of the device from a rest configuration to an actuated configuration, and in the rest configuration the plunger is in the inserted position and the biasing member exerts a minimum biasing force on the plunger, and in the actuated configuration the plunger is in the retracted position and the biasing member exerts a maximum biasing force on the plunger.

[0060] In other words, a device is provided for brewing espresso coffee by manually driving a plunger through the cavity, thereby forcing a quantity of liquid under pressure through a quantity of ground coffee. The plunger is driven by a biasing member, which is provided with potential energy through the use of an actuator by a user to change the configuration of the device from a resting configuration to an activated configuration. It is therefore the biasing member, rather than the actuator itself, that primarily drives the plunger through the cavity, meaning that the user need only prime the biasing member rather than drive the entire brewing process.

[0061] In other words, a means is provided for brewing espresso coffee in a semi-automatic manner that does not require electrical connections or dedicated plumbing and that requires minimal input from the user. In particular, once the user has performed actuation of the actuator, they may walk away from the device to finish extracting the espresso coffee under the power of the at least one biasing member alone.

[0062] Figure 1 shows a cross-section of an apparatus 100 for brewing espresso coffee according to an embodiment of the present disclosure. In particular, Figure 1 shows the apparatus in a static configuration.

[0063] The device 100 has a cylinder 110 defining a cavity 120 for receiving a liquid, for example, by an opening 140 at the top of the cylinder. The device further has a plunger 130 slidably received in the cavity. The plunger has a plunger shaft 132 and a plunger head 134. In the example described herein, the cavity and plunger head are cylindrical and have a circular cross section. FIG. 1 shows the plunger 130 in an inserted position, i.e., a rest configuration, within the cavity. Features of the plunger head 134 are described in further detail below with reference to FIGS. 5A and 5B.

[0064] A plunger 130, which is received in axially slidable fashion within cavity 120, is attached to an actuator 150 of the device. The actuator has a biasing member 160 for biasing the plunger toward the insertion position. As shown in FIG. 1, in the rest configuration, the biasing member exerts a minimum biasing force on the plunger. In the actuated configuration, the biasing member exerts a maximum biasing force on the plunger.

[0065] The actuator may have an actuation element that can be moved by a user of the device to change the configuration of the device from a resting configuration to an actuated configuration, such as sliding the plunger from an inserted position to a retracted position. For example, when a user performs a first movement with the actuation element, the actuator may cause plunger 130 to move from the inserted position to the retracted position within cavity 120.

[0066] In the examples described herein, the actuation element includes a pivotable element pivotally connected to the cylinder, specifically, a lever 151 pivotally connected to the cylinder 110 and connected to a flange on the clinger, for example, by a pin joint. In the example shown in FIG. 1 , the actuator includes a pair of levers 151 diametrically opposed on opposite sides of the cylinder 110. Thus, a first movement of the actuation element may involve pivoting the lever about its connection point with the cylinder in a first direction. Accordingly, a corresponding second, opposite movement would involve pivoting the lever about its connection point with the cylinder in a second direction opposite the first direction. Using a pair of levers reduces the force required by a user on each lever to move the plunger from one position to another. Furthermore, providing a pair of levers makes the action of moving the actuator more balanced and natural for the user, thereby improving the ease of use of the device for the user.

[0067] The actuator 150 further comprises a compression plate 152 connected to the actuation element 151 such that movement of the actuation element causes the compression plate to undergo a movement. The actuator 150 also comprises a substrate 153 connected to the plunger 130 such that movement of the plunger causes the substrate to undergo a movement. Movement of the substrate also causes the plunger to undergo a corresponding movement.

[0068] The biasing members 160 shown in FIG. 1 are provided between the compression plate 152 and the substrate 153. The biasing members bias the compression plate and the substrate away from each other. The biasing members are elements of the device that, when at least one biasing member has potential energy, exert a force on the plunger through the substrate coupled thereto, driving the plunger from a retracted position to an inserted position within the cavity. Potential energy is imparted to the biasing members by transitioning between a resting configuration and an actuated configuration, as further described below. For example, the biasing members may include compressible elements adapted to store potential energy when compressed.

[0069] In the examples described herein, biasing member 160 includes a compressible element, particularly a spring such as a compression spring. Potential energy may be imparted to the spring during transition between the rest configuration and the actuated configuration by forcing the compression plate and substrate toward each other, thereby compressing the spring. In the example shown in FIG. 1 , biasing member 160 includes a pair of springs, each coupled to one of a pair of levers 151.

[0070] The actuator 150 may further include an arm 154 pivotally connected to the actuation element and connected to the compression plate at an end of the arm opposite the connection between the arm and the actuation element. According to this example shown in Figure 1, the actuator includes a pair of arms 154, each pivotally connected to one of a pair of levers 151. The arms 154 may be connected to the levers by pin joints 155.

[0071] As shown in FIG. 1 , biasing member 160, specifically a spring, is held within housing 156. The spring is held within the housing such that it can move substantially along a single axis. In the example shown in FIG. 1 , substrate 153 forms the base of the housing. The housing, and more specifically, one end of the housing, is pivotally connected to plunger 130, for example, by pin joint 157. The combination of housing 156, substrate 153, arm 154, and compression plate 152 may act in a manner similar to a piston as the arm and compression plate move within the housing.

[0072] The base plate 153, provided at the end of the housing 156 opposite the end connected to the plunger 130, may include an opening or through-hole through which the arm 154 may slide. Thus, the base plate 153 shown in FIG. 1 is an annular plate. One end of the biasing member 160 abuts the base plate 153, which forms the base of the housing 156. The arm and compression plate 152 are arranged at least partially within the housing such that the arm passes through the opening in the base plate and through the central cavity of the spring, and the other end of the spring (the end opposite the end abutting the base plate) rests on the underside (i.e., compression surface) of the compression plate 152. Thus, the spring is compressed by the compression plate moving toward the base plate and away from the connection between the housing and the plunger. The spring is therefore decompressed by the base plate moving away from the compression plate.

[0073] The spring 160 may be pre-tensioned before being inserted into the housing, meaning that when fully extended within the housing 156, the spring still exerts a force against the compression plate 152 and base plate 153 and plunger 130. In this way, it is possible to reduce or eliminate the drop in pressure towards the end of the extraction process as the spring reaches its maximum possible extension and the plunger approaches the inserted position.

[0074] The device 100 depicted in FIG. 1 also shows a receptacle 170 for placing a quantity of ground coffee adjacent the base of the cylinder 180, the receptacle having an arrangement of a portafilter 172 and a filter basket 174. The filter basket holds a quantity of ground coffee and, under pressure, allows water but not coffee powder to pass through. The portafilter has a means for holding the filter basket in place, a handle, and an outlet 176 for the brewed coffee. In the example shown in FIG. 1, a protrusion 178 on the outside of the portafilter engages with threads on the device to hold the portafilter tightly and sealingly against the base of the cylinder 180.

[0075] The receptacle 170 for placing a quantity of ground coffee adjacent the base of the cylinder 180 may also include a restrictor that acts to restrict the flow of water through the ground coffee under the pressure of the actuated plunger 130. By providing such a restrictor, the pressure required for extraction of espresso coffee will be reached by the device regardless of the fineness of the ground coffee provided by the user. The restrictor will therefore improve the ease of use of the device, especially for unskilled users, and will improve the quality of the extracted coffee.

[0076] Operation of device 100 will now be described with reference to Figures 1-3. The device begins in a rest configuration, as shown in Figure 1, with the actuating element and biasing member in a rest position, with the biasing member exerting a minimum biasing force on the plunger and the plunger in its inserted position within the cavity. As shown in Figure 1, the rest position of the actuator corresponds to a pair of levers 151 located on opposite sides of the cylinder being in a downward position adjacent the cylinder, and the rest position of biasing member 160 corresponds to the spring being in its maximum possible decompressed state, limited by housing 156.

[0077] With the machine 100 in this state, a user may provide ground coffee to the machine to brew an espresso coffee. For example, a user may fill the filter basket 174 with a quantity of ground coffee and place the filter basket adjacent the base of the cylinder with a means to hold it in place, such as a portafilter 172. The user may then provide a liquid, such as heated water, to the cavity 120 in the cylinder. The liquid may be provided to the cylinder through an opening in the top of the cylinder. In the example described herein, the liquid received in the cavity may be water heated to 90°C to 96°C.

[0078] After the ground coffee and liquid are provided to the device 100, the user uses the actuator to change the device's configuration from the resting configuration to the operating configuration. For example, the user may raise the pair of levers 151 from a lowered position to an elevated position in a first movement, i.e., the user may use the levers to perform a pivotal movement in a first direction. Because the arms 154 and housing 156 are rigid and the compression plate 152 abuts the housing, such movement with the levers causes the arms 154, compression plate 152, housing 156, base plate 153, and biasing member 160 to all move in response to the lever movement without the compression plate and base plate approaching each other or the biasing member being compressed. Thus, the fixed connection points between the actuating element and the compression plate and between the plunger and base plate will cause the plunger 130 to slide from the inserted position to the retracted position. The plunger may include a one-way valve mechanism to allow liquid to pass from above the plunger head to below the plunger head as the plunger moves from the inserted position to the retracted position, as will be described in more detail below with reference to Figures 5A and 5B.

[0079] Between the rest configuration and the working configuration, there is an intermediate configuration of the device in which the plunger 130 is in the retracted position, the actuating element (e.g., lever 151) is in an inclined position relative to the cylinder, and the biasing member still exerts a minimal biasing force on the plunger. In this configuration, the liquid is held unpressurized in the cavity between the plunger 130 and the ground coffee. To achieve the working configuration, the user may perform a second movement of the actuating element opposite to the first movement. For example, the user may lower the lever 151 from the raised position back to its original lowered or rest position. Such movement initiates the plunger sliding back toward the inserted position; however, movement of the plunger from the retracted position to the inserted position is resisted by the water between the plunger and the ground coffee. FIG. 2 shows the device 100 in a state between the rest configuration and the working configuration.

[0080] When the force required to cause the water to pass through the ground coffee exceeds a predetermined threshold, movement of the lever 151 during the second movement will cause the compression plate 152 and base plate 153 to be brought together, thereby compressing the spring. In particular, the resistance provided by the water in the cavity will prevent the plunger from reaching its insertion position in the cavity, which means that the plunger will remain in a substantially retracted position when the lever is lowered. To account for this difference from the original state of the device, the compression plate and base plate (connected to the actuating element and plunger, respectively) are brought together and the biasing member is compressed.

[0081] FIG. 3 shows the device 100 in an activated configuration. In particular, FIG. 3 shows the lever 151 returned to the rest position shown in FIG. 1; however, the spring 160 is fully compressed between the compression plate 152 and the base plate 153, and the plunger is in a retracted position. The compressed spring will exert a force on both the compression plate and the base plate to release stored potential energy and return to their resting states. Because the compression plate cannot move upward due to the arm 154 connecting the compression plate to the lever and fixing its position relative to the cylinder, the housing 156 and attached plunger 130 are forced to move downward, which drives the plunger toward its insertion position within the cavity 120. The driven plunger therefore applies pressure to the liquid in the cavity, forcing the liquid through the ground coffee and completing the extraction process.

[0082] If the lever were directly connected to the plunger without a spring-like biasing member, the user would need to apply force to the lever for the entire brewing time until the plunger returned to its inserted position and the liquid exited the cavity and passed through the ground coffee. Such continuous application of force would be burdensome for certain users, especially for a typical brewing time of approximately 30 seconds to reach the relatively high pressures required to brew an espresso. By providing a spring-like biasing member, the user may complete the second movement in a single fluid movement that takes, for example, only 2 seconds, after which the brewing process would be complete without further user input. Furthermore, by providing a pair of levers, each lever attached to the plunger by a separate spring, the force required to be applied by the user to each lever would be reduced without reducing the amount of pressure delivered to the liquid in the cavity, and would not adversely affect the quality of the brewed coffee.

[0083] FIG. 4 is a perspective view of the apparatus 100 described with respect to FIGS. 1-3. As shown in FIG. 4, the apparatus may further include a stand 210 having multiple legs 220, such as two legs. The stand provides space underneath for a container, such as a cup, to receive coffee brewed by the apparatus. In the example shown in FIG. 4, the stand has two legs having a generally arcuate shape. The apparatus may further include a platform 230 connected to the stand. The platform 230 may have an outer rim 240 for containing spills. The platform may also have a series of raised formations (not shown) to keep a container placed on the platform from contacting the topside of a substrate and, accordingly, from contacting liquid that may drip onto the substrate during use of the apparatus.

[0084] The device may also have a pressure gauge (not shown) for measuring the pressure in the cavity as the plunger slides from the retracted position to the inserted position. The measured pressure may be provided to the user by any suitable display means to enable the user to more accurately monitor the brewing of the coffee.

[0085] Figures 5A and 5B show in more detail the head 134 of the plunger 130. In particular, Figure 5A shows the head of the plunger when liquid may pass through it, and Figure 5B shows the head of the plunger when liquid cannot pass through it.

[0086] The head 134 of the plunger 130 is sized and shaped to easily slide axially within the cavity 120 under the force of an actuator and / or biasing member, as described above. The plunger head is fitted with an outer O-ring 310 to seal the outside of the plunger head 300 against the inner wall of the cylinder 110.

[0087] The O-ring 310 may adopt a position adjacent to a lower flange 320 molded on the outer periphery of the plunger head 300, or a position lying against an upper flange 330 that is also integrally molded. When the plunger 130 slides within the cavity 120 from the inserted position to the retracted position, the O-ring moves to lie adjacent to the lower flange 320. When the plunger slides from the retracted position to the inserted position, the O-ring rolls to lie against the upper flange 330.

[0088] As shown in FIGS. 5A and 5B , the plunger head has one or more apertures 340 extending from the adjacent lower flange 320 approximately halfway through the space between the lower and upper flanges 330. When the O-ring 310 is adjacent the lower flange 320, for example, when the plunger is sliding from the inserted position to the retracted position, there is correspondingly space to allow water to pass between the side of the plunger and the wall of the cylinder 110, through the aperture 340, and into the space below the plunger head 300. When the plunger slides from the retracted position to the inserted position, the O-ring moves to lie against the upper flange 330, thereby forming a complete seal around the entire circumference of the plunger head 300, allowing water to pass under pressure through the ground coffee held below the cylinder 110. The upper edge of the plunger head may be cushioned by one or more notches 350 to assist in the flow of water downward through the plunger head 300 as it slides within the cavity from the inserted position to the retracted position.

[0089] Figures 6 and 7 show an apparatus 100' according to a further embodiment. In particular, Figure 7 shows the apparatus between a static configuration and an active configuration, and Figure 8 shows the apparatus in an active configuration. In these figures, reference numerals are repeated when referring to features already described above.

[0090] As described above, the actuator has a biasing member for biasing the plunger 130 toward the insertion position. In the example shown in Figure 6, the actuating element has a pair of levers 151, and the biasing member has a spring 400.

[0091] As shown in Figure 6, spring 400 is at least partially held within cavity 120 of cylinder 110. The spring is held within the cavity so that it can move substantially only along a single axis. The body of plunger 130 may pass through the central cavity of the spring such that the spring is located between the plunger body and the wall of the cavity.

[0092] The actuator includes a compression plate 410, which is an annular plate provided around the shaft of the plunger 130 and is axially slidable along the shaft. The plunger, particularly the plunger shaft, may freely pass through a central through-hole in the compression plate. The compression plate is connected to the actuation element 151 such that movement of the actuation element causes the compression plate to undergo a corresponding movement. The actuator also includes a substrate 420, which is an annular plate provided around the shaft of the plunger and is connected to the plunger 130 such that movement of the plunger causes the substrate to undergo a corresponding movement. Movement of the substrate also causes the plunger to undergo a corresponding movement. The substrate 420 may be disposed proximal to the head of the plunger. In the examples shown in FIGS. 6 and 7, the substrate is integrated with the head of the plunger.

[0093] A spring 400 is provided between a compression plate 410 and a substrate 420, with one end of the spring abutting the top surface of the substrate and the other end of the spring abutting the bottom surface of the compression plate. The spring is therefore compressed by moving the compression plate and the substrate towards each other. The spring is therefore decompressed by moving the compression plate and the substrate away from each other.

[0094] Again, the actuator may further include an arm 430 pivotally connected to the actuation element and connected to the compression plate 410 at an end of the arm opposite the connection between the arm and the actuation element. According to this example shown in Figure 6, the actuator includes a pair of arms 430, each pivotally connected to one of a pair of levers 151. The arms 430 may be connected to the levers by pin joints. Furthermore, each arm is pivotally connected to the compression plate 410, such as by a pin joint, at an end of the arm opposite the connection between the arm and its respective lever.

[0095] In use, the device operates in much the same manner as described above with reference to Figures 1-3. When the device is changed from the resting configuration to the operating configuration (e.g., as the lever moves from the resting position to the configuration shown in Figure 6 and then to the configuration shown in Figure 7), the compression plate 410 moves toward the base plate 420, compressing the spring 400. As shown in Figure 7, the compression plate 410 is rigidly connected to the lever 151 by the arm 430, which means that the force exerted by the spring 400 can only act to drive the base plate and plunger 130 from the retracted position to the inserted position within the cavity 120. The driven plunger therefore applies pressure to the liquid in the cavity, forcing the liquid through the ground coffee and completing the extraction process.

[0096] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, may be expressed in their specific form, or in terms of means for performing a disclosed function, or methods or steps for obtaining a disclosed result, as appropriate, and may be utilized to realize the invention in various of its forms, either separately or in any combination of such features.

[0097] While the present invention has been described in conjunction with the above exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art given this disclosure. Accordingly, the above exemplary embodiments of the present invention are considered to be illustrative and not limiting. Various changes may be made to the described embodiments without departing from the spirit and scope of the invention.

[0098] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purpose of enhancing the understanding of the reader, and the inventors do not wish to be bound by any of these theoretical explanations.

[0099] Any headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

[0100] Throughout this specification (including the claims which follow), unless the context requires to the contrary, the words "comprise" and "include", and variations such as "comprises", "comprising" and "including", will be understood to imply the inclusion of a stated integer, step or group of integers or steps, but not the exclusion of any other integer, step or group of integers or steps.

[0101] It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. As used herein, ranges may be expressed as from "about" one particular value and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations by use of the antecedent "about," it will be understood that the particular value forms another embodiment. The term "about" with respect to numerical values ​​is optional and can mean, for example, ±10%.

Claims

1. 1. An apparatus for brewing espresso coffee, the apparatus comprising: having a cylinder defining a cavity for receiving a liquid; a plunger axially slidable within the cavity between an inserted position and a retracted position; and an actuator having a biasing member for biasing the plunger toward the insertion position; the actuator is adapted to change the configuration of the device from a rest configuration in which the plunger is in the inserted position and the biasing member exerts a minimum biasing force on the plunger to an actuated configuration in which the plunger is in the retracted position and the biasing member exerts a maximum biasing force on the plunger. The device.

2. The actuator further comprises: a compression plate; and a substrate, the substrate being connected to the plunger; the biasing member is provided between the compression plate and the substrate; 10. The apparatus of claim 1.

3. In the static configuration, the compression plate and the substrate have a maximum spacing therebetween; and in the activated configuration, the compression plate and the substrate have a minimum spacing therebetween; 3. The apparatus of claim 2.

4. 4. The apparatus of claim 2, wherein in the actuated position, the compression plate is fixed relative to the cylinder and the base plate is movable relative to the cylinder in response to the biasing force, such that the plunger can be driven towards its insertion position.

5. 5. The device of any one of claims 2 to 4, wherein the actuator has an actuating element that is movable to change the configuration of the device from the rest configuration to the actuated configuration.

6. The device of claim 5 , wherein the compression plate is connected to the actuation element.

7. The apparatus of claim 6 , wherein the actuator further comprises an arm connecting the compression plate to the actuation element.

8. The device of claim 7 , wherein the arm is pivotally connected to the actuation element.

9. An apparatus according to any one of claims 7 to 8, wherein the arm is pivotally or fixedly connected to the compression plate.

10. The apparatus of any one of claims 7 to 9, wherein the actuator further comprises a housing containing the biasing member, and the substrate forms a base of the housing.

11. The apparatus of claim 10 , wherein the compression plate is axially slidable within the housing.

12. A device according to any one of claims 10 to 11, wherein the housing is pivotally connected to the plunger.

13. The device according to any one of claims 7 to 9, wherein the substrate is an annular plate and surrounds the shaft of the plunger.

14. 14. The device of claim 13, wherein the compression plate is an annular plate and surrounds the shaft of the plunger.

15. 15. The device of claim 14, wherein the compression plate is axially slidable on the shaft of the plunger.

16. An apparatus according to any one of claims 5 to 15, wherein the actuating element comprises a pivotable element pivotally connected to the cylinder.

17. 17. The apparatus of claim 16, wherein the pivotable element comprises a lever.

18. An apparatus according to any one of claims 5 to 17, wherein the actuating element comprises a pair of pivotable elements or levers arranged on opposite sides of the cylinder.

19. 10. An apparatus according to any one of the preceding claims, wherein the biasing member comprises a compressible element.

20. 20. The device of claim 19, wherein the compressible element comprises a spring.

21. 21. The device of claim 20, wherein the spring is pre-tensioned.

22. 10. A method for brewing espresso coffee using a device for brewing espresso coffee according to any one of the preceding claims, the method comprising: providing a quantity of liquid to the cavity of the device in the stationary state; actuating the device with the actuator to change the configuration of the device to the actuated configuration; driving the plunger toward its inserted position with the biasing force of the biasing member, thereby forcing the liquid through a quantity of ground coffee. The method.

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