Coffee bean grinder
Patent Information
- Application Number
- EP2023888045
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-11-08
- Publication Date
- 2025-09-17
Smart Images
Figure 1.1
Abstract
Description
Coffee Bean GrinderTechnical field
[0001] The present invention relates to a grinder and, in particular, it relates to a grinder that is adapted to be readily disassembled for cleaning.Background of the Invention
[0002] Grinders for grinding various foodstuffs, such as coffee and spices are commonly known. In such grinders, particles of ground product tend to adhere to interior surfaces, such as walls and grinding elements. Being exposed to air, these particles are oxidised, so periodic cleaning is needed to avoid the accumulation of this degraded material. Typically, a user might invert the grinder and shake particulate matter out, however, this may not remove all such material. Proper cleaning can be achieved with tools such as scrapers and brushes, but requires disassembly to access to all of the small spaces within the grinder. Such disassembly is complicated, time-consuming and may require the use of additional hand tools to be completed satisfactorily.
[0003] The patent publication CN112603168A describes a coffee bean grinder in which both grinding elements can be removed, for cleaning, as parts of a sub-assembly in which they are mounted. However, this solution suffers from being relatively mechanically complex and costly to make, as the removable grinding sub-assembly incorporates both an adjuster ring that is rotated to vary the axial spacing between the grinding elements and associated mechanism, as well as a 90 degree bevel gear pair and a coupler by which it is driveably and removably connected to a transverse shaft driven by the motor. It is an object of the present invention to overcome or substantially ameliorate the above disadvantages or, more generally, to provide an improved grinder.
[0004] Disclosure of the Invention
[0005] According to one aspect of the present invention there is provided a grinder including:
[0006] a motorised drive having a rotary output that rotates about an axis;
[0007] a housing holding the motorised drive;
[0008] a recess that extends generally axially into the housing to the rotary output, the recess defining an opening at an axially outer end of the recess;
[0009] an adjustment mechanism for adjusting the fineness of ground product, the adjustment mechanism comprising a carrier through which the axis extends, the carrier including a first mating part;
[0010] a cup insertable axially into the recess through the opening, the cup having a mouth;
[0011] a first grinding element mounted in the cup for rotation about the axis;
[0012] a coupler for transmitting torque from the rotary drive to the first grinding element, the coupler mounted on an inner axial end of the first grinding element and engageable with the rotary output by relative axial movement;
[0013] a second grinding element insertable axially into the mouth to cooperate with the first grinding element and define a gap therebetween that determines the fineness of ground product, the second grinding element having a second mating part that engages the first mating part, whereby the second grinding element is carried on the carrier;
[0014] a coupling between the cup and the second grinding element, the coupling accommodating axial displacement of the second grinding element relative to the cup for varying the size of the gap, and including respective abutment faces on the cup and the second grinding element, such that outward axial displacement of the second grinding element brings the abutment faces into mutual engagement to pull the cup axially out of the recess.
[0015] The adjustment mechanism for adjusting the fineness of ground product, by relative axial displacement of one of the first and second grinding elements, is a known mechanism operated manually by the user, as by rotation of a knob or lever.
[0016] Preferably the coupling for connecting the cup and the second grinding element is a first bayonet-type (push-and-turn) coupling. Alternatively, the coupling may take other forms, particularly known forms of coupling which are engaged and disengaged by relative rotation. For instance, one of the cup and the second grinding element could include a separate coupling collar mounted to rotate about the axis to connect the cup and the second grinding element.
[0017] Preferably the first bayonet-type coupling comprises an interface between surfaces that are complementary and coaxial with the axis, one of the surfaces external on the second grinding element and the other of the surfaces on the cup surrounding the second grinding element, a projection extending radially from one of the surfaces across the interface is received in a channel in the other of the surfaces, the channel comprising an axially-extending leg that intersects a circumferentially-extending leg, whereby a blind end of the circumferentially-extending leg and an opposing edge of the axially-extending leg bound the axial guide portion and the abutment faces are formed on the projection and the circumferentially-extending leg. Alternatively, a bayonet-type coupling may comprise a circumferential slot into which a shank of an axially extending fastener is received following rotation, with a head of the fastener securing the parts against axial separation.
[0018] In an embodiment, the projection comprises a projection member slidably received in an opening in the second grinding element for movement between an extended position and a retracted position, wherein a spring urges the projection member to the extended position.
[0019] The carrier may be mounted for rotation about the axis, and restrained from axial movement, the second mating part compromises a projection and the first mating part comprises a screw thread in the carrier that receives the projection.
[0020] Alternatively, the carrier may mounted for reciprocation along the axis, and restrained from rotating about the axis, the second mating part compromises a projection and the first mating part comprises an L-shaped channel of a second bayonet-type coupling, and further comprising an adjuster ring coaxial with the axis and engaging the carrier, the adjuster ring comprising a screw thread by which the adjuster ring is displaced axially.
[0021] Preferably the second grinding element further comprises a handle of semi-circular form, fixed at its ends to turn about a diametrical axis between a stowed position in which the handle is generally disposed in a radial plane and a deployed position in which the handle is generally disposed in an axial-transverse plane.
[0022] Preferably the second grinding element comprises an annular flange projecting outwardly from the one of the surfaces external on the second grinding element, and which is assembled to overly a rim of the cup.
[0023] Preferably the coupling between the cup and the second grinding element further comprises a detent that holds the second grinding element and the cup in an assembled state.
[0024] This invention provides a grinder which that is readily disassembled without the need for tools and which has an overall simple design which minimizes manufacturing costs and maximizes performance. Advantageously, it may be a stand-alone appliance or one incorporated onto a different machine, such as a coffee maker.Brief Description of the Drawings
[0025] Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:
[0026] Fig. 1 is a pictorial view of a coffee bean grinder of a first embodiment of the invention, shown assembled ready for use;
[0027] Fig. 2 is an exploded pictorial view of the coffee bean grinder of Fig. 1;
[0028] Fig. 3 is an exploded pictorial view of the grinding sub-assembly of Fig. 2, together with the carrier;
[0029] Fig. 4 is an exploded view of the grinding sub-assembly of Fig. 2 sectioned in an upright central plane;
[0030] Figs 5A and 5B are schematic sections in an upright plane through the grinding sub-assembly of Fig. 1, showing the second grinding element connected to the cup at axially outer and axially inner positions, respectively;
[0031] Fig. 6 is a section in a transverse plane through a variant of the grinding sub-assembly of Fig. 2;
[0032] Fig. 7 is a fragmentary section in an upright plane through the assembled grinder of Fig. 1;
[0033] Fig. 8 is a fragmentary section in an upright plane through the assembled grinder of a second embodiment of the invention;
[0034] Fig. 9 is an exploded pictorial view of the grinding sub-assembly of the grinder of Fig. 8, together with the carrier, and
[0035] Fig. 10 is a pictorial view of the projection of Fig. 9.
[0036] Description of the Preferred Embodiments
[0037] Referring to Figs 1 and 2, a first embodiment of a grinder 10, particularly for coffee beans, includes a housing 11 that holds a motorised drive 12 with a rotary output 37 that rotates about an axis 17. The grinder 10 may be a stand-alone benchtop appliance, in which the housing 11 is adapted rest upright on a horizontal surface while supporting on its upper end 13 a hopper 14 for holding product to be ground, such as coffee beans. A recess 16 extends generally axially into the housing 11, as from the upper end of the housing 11, to the rotary output 37. A grinding sub-assembly 15 is demountably secured in a recess 16 in the upper end 13 in coaxial alignment with the axis 17 and can be readily removed and disassembled for cleaning.
[0038] As used herein, except where the context requires another meaning, the term “axial” refers to a direction substantially parallel to the axis 17. The term “radial” refers to a direction substantially orthogonal to the axis 17. The term “circumferential” refers to the direction of a circular arc having a radius substantially orthogonal to the axis 17.
[0039] A locating ring 18 may surround the recess 16 and bound an opening 19 at an axially outer end of the recess 16. The locating ring 18 may be fixed to the housing 11, and have a form complementary to the lower end of the hopper 14 in which it is received, thus serving to locate and support the hopper 14.
[0040] Mounted axially inwardly of the locating ring 18, is a carrier 20 mounted to the housing 11 for limited rotation about the axis 17. The carrier 20 may be annular, with a central opening 92 disposed coaxially with the axis 17. Fasteners 53 (see Fig. 7) may extend axially through circumferential slots 21 in the carrier 20 to connect the housing 11 to the locating ring 18, while accommodating the carrier 20 therebetween in a manner that substantially prevents the carrier 20 moving axially, while permitting it to rotate about the axis 17. The outer circumference of the carrier 20 may be ribbed, or the like, for better grip when manually turning the carrier 20. The carrier 20 includes an internal screw thread 23 that generally extends circumferentially inside the recess 16 and cooperates with the grinding sub-assembly 15 and, in this manner, provides an adjustment mechanism for adjusting the fineness of ground product.
[0041] The motorised drive 12 fixed internally in the housing 11 may comprise a rotary electric motor 36 that drives the rotary output 37 via a gearbox 38 that provides speed reduction and torque multiplication. Coffee beans, for instance, drop through an inlet 24 at an axially outer end of the grinding sub-assembly 15 which, driven by the motorised drive 12, grinds the beans to produce ground coffee that is ejected generally radially from the outlet 25, from which it falls to be dispensed from the nozzle 26.
[0042] Referring to Figs 3 and 4, the grinding sub-assembly 15 includes a cup 27 in which a first grinding element 28 is supported for rotation about the axis 17 and a cooperating second grinding element 29 such that there is relative rotation between these grinding elements 28, 29. The cup 27 may have a cylindrical wall 30 that forms a mouth 31 at its axially outer end and surrounds the first grinding element 28, with the outlet 25 formed an axially inner end of the cylindrical wall 30. The first grinding element 28 may comprise external cutting teeth configured in a tapered manner, as in a frustoconical portion 63 that narrows toward the mouth 31. The first grinding element 28 may be fixed on a spindle 32 mounted in bearings 33a, 33b to rotate about the axis 17. The rotary first grinding element 28 may further include a toothed inner portion 64, disposed axially inwardly of the frustoconical portion 63, and having radially outer edges 65 that sweep a circular path adjacent an internal cylindrical surface 35 of the cylindrical wall 30. The inner portion 64 may have an axial dimension approximately equal to that of the outlet 25 to which it directs the ground coffee. An axially inner end of the base of the cup 27 may include an annular portion 66 with which the bearings 33a, 33b are engaged and about which the inner portion 64 of the first grinding element 28 extends, as at complementary faces 67 thereof that taper to narrow toward the mouth 31. A nut 34 may engage a threaded axially outer end of the spindle 32 to fix the first grinding element 28 to the spindle 32. Torque is supplied to the spindle 32 from the rotary output 37 with one coupler part on an inner axial end of the first grinding element comprising internal splines 39 and another coupler part on the rotary output 37 comprising complementary external splines 40. In this manner, the splines 39, 40 are mutually engageable to transmit torque therebetween, while being engaged by relative axial sliding movement when the cup 27 is lowered axially into the recess 16 through both the opening 19 and the carrier 20, and disengaged when withdrawn axially from the recess 16.
[0043] The second grinding element 29 may comprise coaxial inner and outer ring-shaped components 42, 43 fixed together, with the inner ring-shaped component 43 comprising internal cutting teeth arrayed around the axis 17 to cooperate with the first grinding element 28 and define a gap therebetween. The inner ring-shaped component 43 may taper to narrow from the inlet 24 to a throat 48. The gap may be approximately annular, its width varying according to the spacing between grinding elements 28, 29 and thereby limiting the fineness of the grind. The outer ring-shaped component 42 may comprise an external cylindrical surface 44, outwardly of which an integral annular flange 45 projects. The second grinding element 29 may have mating parts in the form of three equally circumferentially spaced nubs 41a, 41b (the third nub is not shown) formed on the annular flange 45 that engage in respective starts 50a, 50b, 50c of the internal screw thread 23.
[0044] The second grinding element 29 may further comprise a handle 46 in the form of a semi-circular loop, hingedly fixed at its ends to rotate about a diametrical axis 47. The handle 46 rotates between a stowed position (shown in dashed outline in Fig. 2) in which the handle 46 rests on the annular flange 45 and is generally disposed in a radial plane and a deployed position (shown in the figures) in which the handle 46, having been rotated by 90 degrees from the stowed position, extends from the outer axial end of the second grinding element 29 and is generally disposed in an axial-transverse plane in which the axes 17, 47 lie.
[0045] The inner axial end of the second grinding element 29 is insertable axially into the mouth 31, where it is retained by a bayonet-type coupling 49 (also sometimes referred to as a push-and-turn coupling) that connects the cup 27 and second grinding element 29 to form the grinding sub-assembly 15.
[0046] The bayonet-type coupling 49 may comprise the external cylindrical surface 44 which is received within the internal cylindrical surface 35 of the cup 27, providing a circular interface with a free running fit between these two components. The second grinding element 29 may further comprise like projections 51a, 51b, 51c that extend radially outward from the external cylindrical surface 44 and are equally circumferentially spaced for receipt in respective channels 52a, 52b, 52c in the internal cylindrical surface 35. The channels 52a, 52b, 52c are of like form, each comprising an axially-extending leg 54 that extends axially inward from the mouth 31 and intersects with a circumferentially-extending leg 55 that extends circumferentially in a like orientation therefrom to an axially-aligned blind end 56.
[0047] To make the bayonet-type coupling 49, the second grinding element 29 is pushed into the mouth 31, moving the projections 51a, 51b, 51c along the axially-extending leg 54 before it is turned, the relative rotation moving the projections 51a, 51b, 51c into the circumferentially-extending leg 55, as to the position shown in Fig. 5A, where axially-outer abutment faces 59 of the projections 51a, 51b, 51c are adjacent circumferentially extending axially outer abutment faces 60 of the circumferentially-extending legs 55. With the second grinding element 29 at the axial position shown in Fig. 5A, the user may turn the carrier 20 to displace the second grinding element 29 axially inwardly relative to the cup 27 to produce more finely ground coffee. The full range of this relative displacement is accommodated within the bayonet-type coupling 49, as illustrated in Fig. 5B, where the axial movement may be limited by the projections 51a, 51b, 51c abutting the axially-inner circumferential edge 62 of the channels 52a, 52b, 52c, disposed opposite the abutment faces 60. The blind end 56 and an opposing edge 57 of the axially-extending leg 54 bound an axial guide portion 58 that cooperates with the projections 51a, 51b, 51c to restrain relative rotation between the cup 27 and the second grinding element 29 about the axis 17. When moved between the position of Fig. 5A to that of Fig. 5B, the projections 51a, 51b, 51c tend to slide along the blind end 56 which prevents the second grinding element 29 rotating together with the carrier 20. Likewise, when the carrier 20 is rotated in the opposite direction, the relative rotation between the second grinding element 29 and cup 27 is restrained by the edges 57 abutting the projections 51a, 51b, 51c.
[0048] Fig. 6 shows a variant of the grinding subassembly 15 in which a magnetic detent is provided for holding the second grinding element 29 and the cup 27 in their assembled state, as in the angular positions shown in Figs 5A and 5B, and which comprises first and second arrays 90, 91 of permanent magnets fixed to the second grinding element 29 and cup 27 respectively. The first array 90 may comprise permanent magnets 90a-90h circumferentially spaced and recessed in an internal wall of the cup 27, each outboard of a respective permanent magnet 91a–91h of the second array 91. The permanent magnets 90a-90h, and 91a-91h may be elongated axially, with their polar axes aligned axially and the magnets of each array 90, 91 having common polarity, the polarity of the second array 91 opposing that of the first 90 such that the magnetic detent operates on attraction between opposite poles. By the use of permanent magnets 90a-90h, 91a-91h acting on one another at a distance, in this manner, the relative axial displacement illustrated is accommodated, while providing a light detent action against rotation that thus tends to hold the second grinding element 29 and cup 27 in their assembled state.
[0049] In use, by making the bayonet-type coupling 49 as described above, the cup 27 and second grinding element 29 are assembled to form the grinding sub-assembly 15 which is then inserted axially as a unit into the recess 16 through both the opening 19 and the central opening 92 in the carrier 20, with the outlet 25 positioned for registration with the nozzle 26. Internal features (not shown) may serve to guide the grinding sub-assembly 15 axially in the correct angular orientation about the axis 17, while also preventing rotation of the cup 27. The carrier 20 is angularly positioned in its disengaged position to ensure that the starts 50a, 50b, 50c are axially aligned with the nubs 41a, 41b as these parts are mutually engaged toward the end of this axial movement, while the internal splines 39 and external splines 40 are likewise mutually engaged. Enclosing the grinding sub-assembly 15 in a recess 16 in the housing 11 in this manner, advantageously provides a compact appliance that is quiet in operation, with a simple structure that can be manufactured cost-effectively. After putting the handle 46 in its stowed position clear of the mouth 31, the hopper 14 is may be placed over the locating ring 18, and the grinder 10 is thus assembled ready to grind coffee beans. Fig. 7 shows a valve assembly 86 which may be provided at the lower end of the hopper 14 to prevent product dropping out. The valve assembly 86 may comprise a valve member 87 fixed to a knob 88 and mounted to a base 89 of the hopper rotate about the axis 17, whereby openings in the base 89 and the valve member 87 are angularly aligned to allow the product to drop out. Once coupled in this way, before operation the user rotates the carrier 20, as described above, to move the second grinding element 29 axially and thereby select the desired fineness of the ground product.
[0050] To assist with disassembly for cleaning, a notch 61 in the locating ring 18 provides access to grasp the handle 46 and rotate it from its stowed position to its extended position. The carrier 20 is angularly positioned in its disengaged position and the handle 46 is grasped to draw out the second grinding element 29. This outward axial displacement of the second grinding element 29 brings the abutment faces 59, 60 into mutual engagement whereby, as a result of this inter-engagement, further outward axial displacement of the second grinding element 29 withdraws the cup 27 from the recess 16. The removed grinding sub-assembly 15 retains loose product within the cup 27 and is then readily disassembled via the bayonet-type coupling 49, to separate the second grinding element 29 from the cup 27.
[0051] Referring to Figs 7 to 10, in a second embodiment of the grinder 210, the adjustment mechanism comprises a carrier 220 and a coaxial adjustment ring 68 that rotates. The carrier 220 that carries the second grinding element 229, while preferably annular, does not rotate about the axis 17 (as in the first embodiment) , but is instead guided to move axially, as described in more detail below. The adjustment ring 68 turns on a screw thread and is coupled to the carrier 220 to thereby control the axial position of the carrier 220 for the purpose of setting the fineness of the ground product.
[0052] As best seen in Fig. 8, where one half of the grinding sub-assembly 215 is shown assembled in the recess 16, with the other half cut away for clarity. A frame 69 is a structural member fixed inside the housing 211 that serves to mount components, including the rotary output 37 and motor 36, while its axially-outer end is cup-shaped and bounds the recess 16. Extending about the rim 70 of the frame 69 is an external screw thread 71 that is engaged with an internal screw thread 72 on the adjustment ring 68. The carrier 220 has a radially-outwardly projecting rib 73 that is received in an annular groove 75 in the adjustment ring 68 that is adjacent a radially-inwardly projecting shoulder 74. Generally equally angularly spaced around the axis 17 may be helical compression springs 76 with axially opposing ends abutting the frame 69 and the carrier 220, thereby urging the rib 73 against the shoulder 74. The carrier 220 may farther include axially-projecting tabs 77a-77c projecting from its axially inner side and received in a running fit in complementary slots 78 in the frame 69 so as to restrain the carrier 220 from turning, but allow it to be readily displaced axially.
[0053] The carrier 220 may include an inner cylindrical face 79 in which three L-shaped channels 80 of like form are provided, each comprising an axially-extending leg 80 that extends axially inward from a mouth 81 and intersects with a circumferentially-extending leg 82 that extends circumferentially. The nubs 241a, 241b on the second grinding element 229 may be elongate circumferentially and formed on the annular flange 245. The nubs 241a, 241b are slidingly received in respective ones of the channels 80, thereby providing a push-and-turn, or bayonet-type, connection between the second grinding element 229 to the carrier 220 that supports it.
[0054] As in the first embodiment, a bayonet coupling 249 (or push-and-turn coupling) connects the second grinding element 229 to the cup 227 and in this second embodiment may comprise a pair of diametrically opposed projections 251 on the second grinding element 229 and a pair of complementary L-shaped channels 252. The projections 251 from the adjacent external cylindrical surface 244 may comprise members received in radially-aligned openings and urged radially outward by springs, as by the C-springs 83 shown in Fig. 10. By tapering the depth of the channels 252 at the mouth, the projections 251 are resiliently displaced slightly inward when entered into the channels 252. Adjacent their blind ends, the circumferential parts of the channels 252 are stepped deeper in the radially outward direction, such that an audible “snap” is produced when the projections 251 drop over the edge of this step. This provides a helpful audible confirmation to the user that these two assemblies are properly connected, as well as a light detent action holding the second grinding element 229 and the cup 227 in their mutually assembled positions. As in the first embodiment, the projections 251 of course provide abutment faces 84, which may be convex, and which abut flat faces 85 on the cup 227 that are disposed in a radial-circumferential plane when the second grinding element 229 is used to withdraw the cup 227 from the recess 16. In this manner, the grinding sub-assembly 215 is demountably secured in the recess 16 in coaxial alignment with the axis 17 in a like manner to the first embodiment and can likewise be readily removed and disassembled for cleaning.
[0055] Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the scope thereof.
Claims
1.A grinder including:a motorised drive having a rotary output that rotates about an axis;a housing holding the motorised drive;a recess that extends generally axially into the housing to the rotary output, the recess defining an opening at an axially outer end of the recess;an adjustment mechanism for adjusting the fineness of ground product, the adjustment mechanism comprising a carrier through which the axis extends, the carrier including a first mating part;a cup insertable axially into the recess through the opening, the cup having a mouth;a first grinding element mounted in the cup for rotation about the axis;a coupler for transmitting torque from the rotary drive to the first grinding element, the coupler mounted on an inner axial end of the first grinding element and engageable with the rotary output by relative axial movement;a second grinding element insertable axially into the mouth to cooperate with the first grinding element and define a gap therebetween that determines the fineness of ground product, the second grinding element having a second mating part that engages the first mating part, whereby the second grinding element is carried on the carrier;a coupling for connecting the cup and the second grinding element, the coupling accommodating axial displacement of the second grinding element relative to the cup for varying the size of the gap, and including respective abutment faces on the cup and the second grinding element, such that outward axial displacement of the second grinding element brings the abutment faces into mutual engagement to pull the cup axially out of the recess.2.The grinder of claim 1, wherein the coupling for connecting the cup and the second grinding element is a first bayonet-type coupling.3.The grinder of claim 2, wherein the first bayonet-type coupling comprises an interface between surfaces that are complementary and coaxial with the axis, one of the surfaces external on the second grinding element and the other of the surfaces on the cup surrounding the second grinding element, a projection extending from one of the surfaces across the interface is received in a channel in the other of the surfaces, the channel comprising an axially-extending leg that intersects a circumferentially-extending leg, whereby a blind end of the circumferentially-extending leg and an opposing edge of the axially-extending leg bound the axial guide portion and the abutment faces are formed on the projection and the circumferentially-extending leg.4.The grinder of claim 3, wherein the projection comprises a projection member slidably received in an opening in the second grinding element for movement between an extended position and a retracted position, wherein a spring urges the projection member to the extended position.5.The grinder of any one of claims 1 to 4, wherein the carrier is mounted for rotation about the axis, and restrained from axial movement, the second mating part compromises a projection and the first mating part comprises a screw thread in the carrier that receives the projection.6.The grinder of any one of claims 1 to 4, wherein the carrier is mounted for reciprocation along the axis, and restrained from rotating about the axis, the second mating part compromises a projection and the first mating part comprises an L-shaped channel of a second bayonet-type coupling, and further comprising an adjuster ring coaxial with the axis and engaging the carrier, the adjuster ring comprising a screw thread by which the adjuster ring is displaced axially.7.The grinder of any one of claims 1 to 5, wherein the second grinding element further comprises a handle of semi-circular form, fixed at its ends to turn about a diametrical axis between a stowed position in which the handle is generally disposed in a radial plane and a deployed position in which the handle is generally disposed in an axial-transverse plane.8.The grinder of any one of claims 1 to 7, wherein the second grinding element comprises an annular flange projecting outwardly from the one of the surfaces external on the second grinding element, and which is assembled to overly a rim of the cup.