Coffee grinding knife

Abstract

This utility model belongs to the field of kitchen appliance technology and discloses a coffee grinder, comprising: a frustum-shaped main body, which includes a coarse grinding section, a pre-grinding section and a grinding section arranged coaxially along its outer side wall, wherein the diameters of the coarse grinding section, the pre-grinding section and the grinding section increase sequentially; a mounting hole, which is opened along the axial direction at the top center of the frustum-shaped main body and penetrates through the frustum-shaped main body; a first set of blades, located on the side wall of the coarse grinding section, extending obliquely along the axial direction with the blades pointing in the rotation direction of the main body; and a second set of blades, located on the side wall of the pre-grinding section, which are circumferentially distributed and have a circumferential density greater than that of the first set of blades. This utility model uses a frustum-shaped main body with a diameter increasing from top to bottom to form a three-stage grinding structure of coarse grinding section, pre-grinding section and grinding section. Large coffee beans are first initially crushed in the coarse grinding section, then moderately refined in the pre-grinding section, and finally finely ground in the grinding section, which significantly improves the consistency of powder particle size.

Description

Technical Field

[0001] This utility model relates to the field of kitchen appliance technology, and in particular to a coffee grinder. Background Technology

[0002] With the popularization of coffee culture and the increasing demands of consumers for coffee quality, the uniformity of coffee grinding, the controllability of fineness, and the temperature control during the grinding process have become key factors affecting coffee flavor. As the core component of a coffee machine, the structural design of the coffee grinder directly determines grinding efficiency, powder particle size distribution, energy consumption, and the overall lifespan of the machine.

[0003] Most coffee grinders on the market today use a flat or conical structure, with symmetrically arranged straight or beveled teeth. These types of grinders have the following prominent problems in actual use: Traditional grinders are mostly designed with a single grinding zone, lacking a grading mechanism. This results in a mixture of large and fine particles, making it difficult to meet the fine particle size requirements of different brewing methods such as espresso and pour-over. The low density of the blades in the primary grinding zone results in insufficient pushing force, causing coffee beans to tend to accumulate at the top. On the other hand, if the blades in the fine grinding zone are too densely packed, the powder cannot be expelled smoothly, causing localized overheating or even burning, which affects the coffee flavor. Utility Model Content

[0004] The main purpose of this utility model is to provide a coffee grinder that addresses the technical problem that traditional grinders are mostly designed with a single grinding area and lack a graded processing mechanism, resulting in a mixture of large particles and fine powder, making it difficult to meet the fine particle size requirements of different brewing methods such as espresso and pour-over.

[0005] To achieve the aforementioned objectives of this utility model, the first aspect of this utility model provides a coffee grinder, comprising: The main body is shaped like a frustum, and along the outer side wall along the axial direction, it includes a coaxially arranged coarse grinding section, a pre-grinding section and a grinding section, the diameters of which increase sequentially. A mounting hole is formed axially at the center of the top of the frustum-shaped body and extends through the frustum-shaped body for connection with the drive shaft. The first set of cutting teeth is located on the side wall of the coarse grinding section, extends obliquely along the axial direction and the cutting edge points in the rotation direction of the main body; The second set of cutting teeth is located on the side wall of the pre-grinding section, and is distributed in a circumferential ring with a circumferential density greater than that of the first set of cutting teeth. The third set of cutting teeth is located on the side wall of the grinding section, extends obliquely along the axial direction, and has a greater circumferential density than the second set of cutting teeth.

[0006] Furthermore, the multiple sets of cutting teeth are arranged in an asymmetrical staggered pattern in the circumferential and axial directions.

[0007] Furthermore, the first set of cutting teeth has 5-12 cutting teeth.

[0008] Furthermore, the inclination angle of the first set of cutting teeth is 6°–80°. Furthermore, the second set of cutting teeth is composed of multiple circumferentially spaced cutting tooth units, and the grooves of the cutting tooth units have a rhomboid structure.

[0009] Furthermore, another embodiment of the second set of cutting teeth is cutting teeth with a near-parallelogram structure.

[0010] Furthermore, the third set of cutting teeth has a blade-like shape, and the inclination angle of the third set of cutting teeth is 2°–50°.

[0011] Furthermore, another embodiment of the third set of cutting teeth is cutting teeth with a rhomboid structure.

[0012] Furthermore, the mounting hole is either a polygonal hole or a spline hole.

[0013] Furthermore, the frustum-shaped main body is a one-piece molded structure made of metal.

[0014] Beneficial effects: 1. This utility model's coffee grinder blade adopts a frustum-shaped main body with a diameter increasing from top to bottom, forming a three-stage grinding structure: a coarse grinding section, a pre-grinding section, and a grinding section. Large coffee bean particles are first initially broken down in the coarse grinding section, then moderately refined in the pre-grinding section, and finally finely ground in the grinding section. This achieves progressive processing of materials, avoiding the coarse grinding of a single cut, significantly improving the consistency of powder particle size and meeting the needs of various coffee brewing methods. Furthermore, the first set of blades is axially inclined, generating axial thrust during rotation to promote downward material flow and prevent upper blockage; the second and third sets of blades have progressively increasing circumferential density, matching the changing trends of material particle size and improving energy utilization efficiency. In particular, the third set of blades has an inclination angle of 2°–50°, close to the axial direction, which is conducive to forming micro-extrusion and friction grinding, resulting in fine and uniform coffee powder.

[0015] 2. The coffee grinder of this utility model has a non-symmetrical staggered distribution of the various sets of blades in the circumferential and axial directions, which breaks the periodic impact characteristics of the traditional symmetrical structure, effectively disperses the instantaneous load during the grinding process, reduces the vibration and operating noise of the whole machine, and improves the user experience.

[0016] 3. This utility model's coffee grinder features a coarse grinding section with seven-star distributed inclined blades, combining impact force and dynamic balance, suitable for crushing large coffee beans. The pre-grinding section can use either rhomboid grooves or parallelogram-like blades; the former provides bidirectional cutting capability, while the latter facilitates smooth cutting and discharge. The grinding section employs high-density blades or a rhomboid multi-blade structure to increase contact area and grinding precision, achieving a "self-grinding" effect. Multiple blade shapes can be flexibly selected or combined according to application scenarios, enhancing the product's adaptability and functionality. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the coffee grinder blade in Embodiment 1 of this utility model; Figure 2 This is a schematic diagram of the coffee grinder blade in Embodiment 2 of this utility model; Figure 3 This is a schematic diagram of the coffee grinder blade in Embodiment 3 of this utility model.

[0018] in: 2- Coarse grinding section; 21- First group of cutting teeth; 3- Pre-grinding section; 31- Second group of cutting teeth; 4- Grinding section; 41- Third group of cutting teeth; 5- Mounting hole.

[0019] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0021] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly and specifically defined.

[0022] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] Example 1 Reference Figures 1-3 An embodiment of this utility model provides a coffee grinder, comprising: The main body is shaped like a frustum, and along the outer side wall along the axial direction, it includes a coaxially arranged coarse grinding section 2, a pre-grinding section 3, and a grinding section 4, the diameters of which increase sequentially. Mounting hole 5 is opened axially at the top center of the frustum-shaped body and passes through the frustum-shaped body for connection with the drive shaft; The first set of cutting teeth 21 is located on the side wall of the coarse grinding section 2, extending obliquely along the axial direction with the cutting edge pointing in the rotation direction of the main body; The second group of cutting teeth 31 is located on the side wall of the pre-grinding section 3, and is distributed in a circumferential ring with a circumferential density greater than that of the first group of cutting teeth 21. The third set of cutting teeth 41 is located on the side wall of the grinding section 4, extends obliquely along the axial direction and has a circumferential density greater than that of the second set of cutting teeth 31.

[0025] In this embodiment, the coarse grinding section 2, pre-grinding section 3, and grinding section 4 form a continuous, integrated outer wall, with their diameters increasing sequentially from top to bottom along the axial direction, creating a stepped, expanding frustum-shaped profile. This structure allows the coffee beans to undergo a gradual, graded grinding process from coarse to fine during their descent, avoiding overheating or uneven particle size caused by a single, forceful compression. The three-section, diameter-increasing structure of the frustum-shaped main body achieves a step-by-step grinding process from top to bottom: large particles are initially broken down in the coarse grinding section 2, intermediate particles are further refined in the pre-grinding section 3, and fine particles are finely ground in the grinding section 4. This design avoids the uneven grinding and localized overheating problems caused by traditional single grinding zones, improving grinding efficiency and powder consistency.

[0026] Mounting hole 5 is axially formed at the center of the top of the frustum-shaped main body, extending through the entire body, and is used for connection with an external drive shaft (such as a motor output shaft). Preferably, mounting hole 5 is a through hole structure, which facilitates axial insertion and achieves stable transmission.

[0027] The first set of blades 21 is disposed on the outer wall of the coarse grinding section 2, extending obliquely along the axial direction, with its blade tip pointing in the direction of rotation of the frustum-shaped main body (i.e., clockwise or counterclockwise, depending on the motor rotation). This oblique structure can generate a combined axial and radial shearing force during rotation, effectively tearing large pieces of coffee beans. The first set of blades 21 is arranged obliquely along the axial direction, forming a spiral propulsion effect in combination with the rotational motion, which helps to convey materials downward and prevents blockage.

[0028] The second set of blades 31 is located on the side wall of the pre-grinding section 3, and is distributed in a circumferential ring. Its circumferential density is significantly greater than that of the first set of blades 21, meaning that there are more blades per unit circumference. It is used to perform medium grinding on the initially broken coffee particles.

[0029] The third set of cutting teeth 41 is located on the side wall of the grinding section 4. It also extends obliquely along the axial direction, and its circumferential density is greater than that of the second set of cutting teeth 31, forming a high-density cutting array, which is suitable for fine grinding and obtaining coffee powder with uniform particle size.

[0030] The density of the cutting teeth increases progressively in each stage: the first group of cutting teeth 21 < the second group of cutting teeth 31 < the third group of cutting teeth 41, which matches the trend of gradually decreasing material particle size, improves energy utilization efficiency, and reduces ineffective idling and energy consumption.

[0031] Mounting hole 5 penetrates the main body, ensuring that the drive shaft can be deeply connected, improving transmission stability and reducing the risk of vibration and eccentricity.

[0032] Optionally, the multiple sets of cutting teeth are arranged in an asymmetrical staggered pattern in the circumferential and axial directions.

[0033] It should be noted that the first, second, and third groups of cutting teeth 41 are arranged asymmetrically and staggeredly in the circumferential and axial directions. Specifically, the cutting teeth in each group are not aligned on the same axial plane or circumferential phase, but are offset by a certain angle along the circumferential direction, such as 15°-45°, and are also not continuously aligned in the axial height. For example, if a cutting tooth in the first group is located at a certain angle θ, the corresponding position in the second group has no cutting tooth, but the cutting tooth unit is set at a position offset to θ+23°. The asymmetrical staggered arrangement breaks the periodic impact characteristics of the traditional symmetrical structure, effectively disperses the instantaneous load during the grinding process, and reduces the vibration and noise of the whole machine; at the same time, the staggered structure enhances the synergistic shearing effect between the multi-level cutting teeth, so that the material is repeatedly sheared in an interlaced manner between different levels, improving the grinding uniformity and reducing the "powder clumping" phenomenon.

[0034] Optionally, the first set of cutting teeth 21 has 5-12 cutting teeth.

[0035] It should be noted that the first group of cutting teeth 21 has a total of 5-12 cutting teeth, which are evenly distributed on the sidewalls of the coarse grinding section 2. Preferably, the first group of cutting teeth 21 has 7 cutting teeth, and its end face projection is in the shape of a "seven-star", that is, the 7 cutting teeth are distributed at equal angles around the central axis. The 7-tooth structure ensures sufficient impact force while avoiding material retention and increased energy consumption caused by too many teeth.

[0036] Optionally, the tilt angle of the first set of cutter teeth 21 is 6°–80°.

[0037] It should be noted that the tilt angle α of the first set of cutter teeth 21 is defined as the angle between the axial center line of the cutter teeth and the axis of the main body, preferably 6°–80°, and more preferably 20°. This angle range has been experimentally verified to achieve the best balance between material propulsion force and shearing efficiency.

[0038] When the tilt angle is less than 10°, the axial conveying capacity is insufficient, which easily leads to accumulation at the top; when it is greater than 30°, the shearing component weakens, affecting the crushing effect. A tilt angle in the range of 6°–80° can provide sufficient downward thrust to promote material flow while maintaining strong lateral shearing force, achieving efficient primary crushing.

[0039] Optionally, the second set of cutting teeth 31 is composed of multiple circumferentially spaced cutting tooth units, and the grooves of the cutting tooth units have a rhomboid structure.

[0040] It should be noted that the second group of cutting teeth 31 consists of multiple circumferentially spaced cutting tooth units, with chip removal gaps between each unit. The groove portion of each cutting tooth unit has a rhomboid structure. The rhomboid groove structure has bidirectional cutting capability, adapting to motor start-stop or reverse operation conditions; its V-shaped contour helps to concentrate stress at the tip, improving cutting capability.

[0041] Optionally, the third set of cutting teeth 41 has a blade shape, and the inclination angle of the third set of cutting teeth 41 is 2°–50°.

[0042] It should be noted that the third set of blades 41 are blade-shaped, meaning they have sharp edges and a cross-section approximately triangular or trapezoidal. Their inclination angle β is 2°–50°, preferably 5°–8°, close to the axial direction, to enhance the squeezing and friction during fine grinding. The small inclination angle allows the third set of blades 41 to be more closely aligned axially, primarily generating a combination of micro-shearing and squeezing actions during rotation. This is suitable for fine grinding of fine particles, avoiding excessive impact that could lead to powder splashing or overheating. The high-density blade structure forms a dense grinding mesh, significantly improving powder uniformity.

[0043] Optionally, the mounting hole 5 can be a polygonal hole or a spline hole.

[0044] It should be noted that the mounting hole 5 is a multi-faceted hole (such as a hexagonal hole or an octagonal hole) or a spline hole (such as an involute spline or a rectangular spline), with protrusions or grooves on the inner wall that match the drive shaft. The multi-faceted hole or spline hole structure provides a larger contact area and higher torsional strength, ensuring stable transmission at high speeds and preventing slippage or wear.

[0045] Optionally, the frustum-shaped main body is a one-piece molded structure made of metal.

[0046] It should be noted that the frustum-shaped main body is integrally formed from metal, preferably stainless steel (such as SUS420J2), high carbon steel, or hard alloy. The integral structure is manufactured using precision stamping, powder metallurgy, or CNC machining processes.

[0047] The metal material has high strength, high hardness and wear resistance, and can withstand repeated impacts and friction from coffee beans for a long time; the one-piece molded structure eliminates stress concentration and weak points in the connection caused by welding or assembly, and improves structural reliability.

[0048] Example 2 Reference Figure 3 Based on the coffee grinder provided in Embodiment 1, another embodiment of the second set of blade teeth 31 is blade teeth with a near-parallelogram structure.

[0049] As a second form of the second set of cutting teeth 31, the cutting teeth have a near-parallelogram structure, meaning that the two sides of the cutting teeth are parallel or nearly parallel, and are inclinedly arranged on the surface of the pre-grinding section 3 to form an oblique cutting edge. This structure is particularly suitable for coffee beans with high viscosity or high moisture content, because its strong sliding shearing action makes them less prone to sticking. The near-parallelogram cutting teeth have a longer effective cutting edge, forming a continuous sliding cutting action during rotation, reducing impact load and crushing noise; at the same time, the oblique structure helps guide the material down the spiral path, enhancing flowability and preventing material accumulation in the pre-grinding section 3.

[0050] Example 3 Reference Figure 2 Based on the coffee grinder provided in Embodiment 1, another embodiment of the third set of blade teeth 41 is blade teeth with a rhomboid structure.

[0051] As the second form of the third group of blades 41, the blades have a rhomboid structure, meaning each blade has a rhomboid protrusion at the top and four cutting edges, distributed on the surface of the grinding section 4 in an array. This structure achieves multi-directional grinding through the multi-sided cutting edges, increasing the grinding contact area. The rhomboid blades have multi-directional cutting capabilities, ensuring that coffee particles can be effectively acted upon by at least one cutting edge regardless of their orientation when entering the grinding zone; their polyhedral structure can also form micro-grinding cavities between particles, further improving the fineness and consistency of the powder.

[0052] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural or procedural transformations made based on the content of the present utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present utility model.

Claims

1. A coffee grinder, characterized in that, include: The main body is shaped like a frustum. Along the outer side wall of the axial direction, there are coaxially arranged coarse grinding section (2), pre-grinding section (3) and grinding section (4), the diameters of the coarse grinding section (2), pre-grinding section (3) and grinding section (4) increase sequentially. Mounting hole (5) is opened axially at the top center of the frustum-shaped body and passes through the frustum-shaped body for connection with drive shaft; The first set of cutting teeth (21) is located on the side wall of the coarse grinding section (2), extends obliquely along the axial direction and the cutting edge points to the rotation direction of the main body; The second set of cutting teeth (31) is located on the side wall of the pre-grinding section (3), and is distributed in a circumferential ring with a circumferential density greater than that of the first set of cutting teeth (21). The third set of cutting teeth (41) is located on the side wall of the grinding section (4), extends obliquely along the axial direction and has a greater circumferential density than the second set of cutting teeth (31).

2. The coffee grinder according to claim 1, characterized in that, The multiple sets of cutting teeth are arranged in an asymmetrical, staggered pattern in both the circumferential and axial directions.

3. The coffee grinder according to claim 1, characterized in that, The first set of cutting teeth (21) has 5-12 cutting teeth.

4. The coffee grinder according to claim 1, characterized in that, The tilt angle of the first set of cutter teeth (21) is 6°–80°.

5. The coffee grinder according to claim 1, characterized in that, The second set of cutting teeth (31) consists of multiple circumferentially spaced cutting tooth units, and the grooves of the cutting tooth units are in a rhomboid structure.

6. The coffee grinder according to claim 1, characterized in that, Another embodiment of the second set of cutting teeth (31) is cutting teeth with a near-parallelogram structure.

7. The coffee grinder according to claim 1, characterized in that, The third set of cutting teeth (41) has a blade-shaped cutting edge, and the inclination angle of the third set of cutting teeth (41) is 2°–50°.

8. The coffee grinder according to claim 1, characterized in that, Another embodiment of the third set of cutting teeth (41) is cutting teeth with a rhomboid structure.

9. The coffee grinder according to claim 1, characterized in that, The mounting hole (5) is either a polygonal hole or a spline hole.

10. The coffee grinder according to claim 1, characterized in that, The frustum-shaped main body is a one-piece molded structure made of metal.

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