Grinder, coffee machine and grinding method

Abstract

A grinder (1) comprises a grinding tool which is arranged in a container (2) and which is rotatable by a drive and serves to comminute a material that is to be ground. The drive comprises a motor, a shaft (3) driven by the motor, and a brake device (4) by means of which a speed of the shaft (3) can be reduced by contact with the brake device (4), wherein the brake device (4) comprises a friction brake.

Description

[0001] Grinding device, coffee machine and method for grinding

[0002] The present invention relates to a grinding device comprising a grinding tool arranged in a container and rotatable by a drive for comminuting a ground material. The drive comprises a motor, a shaft driven by the motor, and a braking device by means of which a rotational speed of the shaft can be reduced through contact with the braking device. Furthermore, the present invention encompasses a coffee machine and a method for grinding.

[0003] There are grinders, for example for coffee, that have grinding tools that can be driven by a drive comprising a motor. In particular, with coffee grinders whose grinding tool is designed as a flywheel, the degree of grinding, i.e. the particle size of the coffee grounds, also depends on the duration of the grinding process and / or the speed of the grinder. A finer grind requires a longer grinding process or, to speed up the grinding process, a higher speed of the flywheel. For the safety of such grinders, especially in household use, it is necessary that the rotating grinding tools can come to a standstill as quickly as possible after use. This is specified, for example, in the safety standard EN 60335-2-14.As the grinder's usage time and / or the speed of the grinder increase, the time required for the grinder to come to a standstill increases, potentially creating safety risks for the user. This can also limit the grinder's service life.

[0004] DE 12 14 651 A shows a mixer with a brake by means of which a planetary carrier of a planetary gear can be braked to accelerate the rotary motion of the mixer's agitators. To this end, springs press a brake partner of the brake radially outward from a central axis against a drum-shaped inner surface of the planetary carrier. The disadvantage here is that the brake cannot be used to stop the rotary motion of the mixers.

[0005] It is therefore an object of the present invention to provide a grinding device with increased safety and service life. This object is achieved by a grinding device having the features of claim 1.

[0006] According to the invention, the grinding device comprises a grinding tool arranged in a container and rotatable by a drive for comminuting a material to be ground, wherein the drive comprises a motor. The drive also comprises a shaft driven by the motor and a braking device by means of which a rotational speed of the shaft can be reduced through contact with the braking device, wherein the braking device comprises a friction brake. This allows the shaft and thus the grinding device to come to a standstill with increased reliability, which increases the safety of the grinding device and its longevity. Furthermore, the grinding device can comply with the EN 60335-2-14 standard for a longer period.

[0007] Preferably, the friction brake comprises at least one first braking partner and at least one second braking partner, so that braking power can be determined at least partially by the two braking partners and so that a reduction in the rotational speed of the shaft is possible through contact between the at least one first braking partner and the at least one second braking partner. The braking power can be configured to be rotational speed-dependent.

[0008] In one embodiment, the second braking partner comprises a braking element that is non-rotatably connected to the shaft, wherein a rotational speed of the shaft can be reduced by contact between the braking element and the first braking partner. This can further increase braking performance, since the braking element can have a higher frictional resistance on its surface than the shaft. Furthermore, repair of the grinding device can be simplified and, if necessary, can be carried out by replacing the braking element, which leads to reduced material usage in the event of repair and improves the ecological balance of the grinding device.

[0009] Alternatively or additionally, the shaft can also be braked by direct contact between the first braking partner and the shaft. In this case, the second braking partner encompasses the shaft. In another embodiment, the braking element can be formed integrally with the shaft, which can reduce the manufacturing costs of the grinding device.

[0010] The braking device preferably comprises at least one spring, by means of which the at least one first braking partner of the friction brake is pressed against the second braking partner, in particular against the shaft. In this way, braking or a reduction in the speed of the shaft can occur automatically. Furthermore, contact between the shaft and the friction brake can be achieved by moving the first braking partner against a pressure direction of the spring, so that the ends of the at least one spring are compressed.

[0011] In one embodiment, the friction brake comprises at least one brake shoe and / or at least one brake pad, so that the braking device can be designed in a space-saving and cost-effective manner.

[0012] Preferably, the friction brake and / or the first brake partner comprises at least two brake shoes, on the inner side of which, preferably facing the shaft, at least one brake block can be arranged. This enables a more even distribution of the braking force and increased braking performance by allowing the first brake partner to act on the second brake partner from more than one direction.

[0013] The friction brake and / or the at least one brake block is preferably made of composite fibers, which in one embodiment can form a brake lining, whereby a frictional force, on which the braking performance depends, can be increased. The friction brake, in particular the brake shoes, can also comprise a plastic, metal and / or wood, or a mixture thereof. This allows the braking device to be manufactured cost-effectively, so that the grinding device can also be manufactured cost-effectively.

[0014] In one embodiment, the friction brake can be manufactured at least partially using a casting process. In particular, the at least one brake shoe and / or the at least one brake block and / or the brake element can be manufactured using a casting process.

[0015] In a further embodiment, the brake pad made of composite fibers is formed from a layer of composite fibers on at least one inner side of the at least one first brake partner, which inner side is directed towards the at least one second brake partner.

[0016] Preferably, the grinding tool comprises a blade. This allows for a simple design of the grinding device, as only one grinding tool is required. Furthermore, coffee can be ground reliably and repair of the grinding device is simplified, allowing the grinding device to have a longer service life, which can also improve the ecological footprint of the grinding device.

[0017] In one embodiment, the at least one first braking partner is arranged to be movable substantially in a plane that has an angle of between 60 degrees and 120 degrees to a vertical axis of rotation of the shaft, and can press radially against the second braking partner at this angle. This allows the braking device to be arranged compactly in the grinding device.

[0018] The braking device in particular has at least one release element, by means of which the at least one first braking partner can be brought out of contact with the at least one second braking partner. The release element can be mounted in the grinding device so that it can pivot about a horizontal axis.

[0019] The braking device can preferably have a cover which is arranged over the at least one brake shoe and which is pivotably connected to the at least one brake shoe at at least one point, such that contact between the at least one first braking partner and the at least one second braking partner can be broken. This can preferably be made possible by actuating the release element. The contact can be restored in particular by pivoting back the at least one first braking partner, which can preferably be achieved by means of the compressive force of the at least one spring, and / or by pivoting back the release element in order to reduce a rotational force of the shaft. This allows the braking device to be used more easily.

[0020] Preferably, the grinding tool and / or the shaft can be rotated at a speed of up to 32,000 revolutions per minute, and in particular from 9,000 revolutions per minute to 25,000 revolutions per minute, and preferably at a speed of 11,000 revolutions per minute to 22,000 revolutions per minute, and even more preferably at a speed of 13,000 revolutions per minute to 20,000 revolutions per minute. This allows the degree of grinding of the material to be ground to be optimized.

[0021] In one embodiment, the grinding device comprises a switching device by means of which the braking device and / or the motor can be actuated. In particular, the motor can be actuated by the switching device, so that the shaft can rotate upon actuation of the motor, while simultaneously breaking contact between the first braking partner and the second braking partner. By actuating the switching device again or by terminating the actuation of the switching device, the braking device, which can be brought into contact with the braking element by at least one spring, can slow the rotational speed of the shaft.

[0022] The switching device can comprise springs and / or a timer so that the switching element and thus the motor can be switched off automatically, wherein the springs can return the release element to its rest position so that the friction brake can reduce the speed of the shaft.

[0023] In a further embodiment, the switching device comprises at least one switching element by means of which the release element can be actuated in the vertical direction. Actuating the switching element, for example, pressing it, in this case actuates the release element, so that the at least one first braking partner can be brought out of contact with the at least one second braking partner against a compressive force of the spring, allowing the shaft to be rotated.

[0024] The switching device preferably has a substantially vertical structure, wherein an actuation of the switching element in the vertical direction by means of the switching device comprising springs is transferable into a vertical movement of one side of the release element, whereby another side of the release element is adjustable in the opposite direction, whereby the brake shoes are displaceable horizontally along the plane.

[0025] The switching device can, in particular, have a fork element so that a compressive force on the switching element can be distributed more evenly to the release element and / or to actuate the motor. In a further embodiment, actuation of the switching element additionally actuates the motor. Upon termination of actuation of the switching element, the motor switches off and the release element returns to its rest state, so that the spring can bring the at least one first braking partner back into contact with the at least one second braking partner, so that the at least one first braking partner and the at least one second braking partner are in contact with one another and can brake a rotational speed of the shaft.

[0026] The ground material includes, in particular, coffee beans.

[0027] The present invention also relates to a coffee machine with a grinding device which can be designed according to the invention so that a service life of the coffee machine is extended.

[0028] Furthermore, the present invention encompasses a method for grinding which comprises the following steps: a. introducing grinding material into a container of a grinding device; b. switching on the grinding device so that contact between a first braking partner and a second braking partner of a braking device is broken; c. rotating a shaft and comminuting the grinding material by rotating a first grinding tool in the container; d. switching off the grinding device so that the first braking partner is pressed against the second braking partner by a spring and the rotations of the shaft are braked.

[0029] Preferably, step d comprises that the switching off can take place automatically after a predetermined period of time has elapsed.

[0030] The present invention will now be explained in more detail with reference to several drawings. They show:

[0031] Fig. 1 is a plan view of the grinding device,

[0032] Fig. 2 is a sectional view of the shaft and the braking device,

[0033] Fig. 3 is a side view of the grinding device, Fig. 4 is a front view of the grinding device in Fig. 3,

[0034] Fig. 5 is a plan view of the grinding device,

[0035] Fig. 6 is a plan view of the braking device in a cross-section of the grinding device,

[0036] Fig. 7 is a further plan view of the braking device in a cross-section of the grinding device.

[0037] Figure 1 shows a plan view of a grinding device 1 comprising a drive comprising a shaft 3 and a braking device 4 designed as a friction brake. The braking device 4 or the friction brake comprises at least one first braking partner 5 and at least one second braking partner 6. Two first braking partners 5 are pressed radially against the second braking partner 6 by at least one spring 8. The second braking partner 6 comprises a braking element 7 which is connected in a rotationally fixed manner to the shaft 3 and which is in contact with at least one brake block 9. A release element 10 is arranged on one side of the braking device 4 such that it is arranged at least partially beneath the first braking partners 5 and is mounted with a horizontal axis of rotation H, whereby it can release the contact between the two first braking partners 5 and the second braking partner 6, i.e. the braking element 7, upon actuation.

[0038] Fig. 2 shows a side sectional view of the shaft 3 and the braking device 4. The first braking partners 5 are arranged essentially in a plane E, which is at an angle A to the axis of rotation D of the shaft 3, wherein the angle A can be between 90 degrees and 120 degrees. The first braking partner 5 comprises at least one brake shoe 11 and two brake blocks 9, which can form a brake lining and which can, for example, comprise composite fibers. The second braking partner 6 comprises the braking element 7, which is connected to the shaft in a rotationally fixed manner, wherein the brake blocks 9 press against the braking element 7 at the angle A, so that the first braking partners 5 and the second braking partner 6 are in contact with one another and a rotational speed of the shaft 3 can be braked.

[0039] Fig. 3 and Fig. 4 show side views of the grinding device 1, which has a container 2. The speed of the shaft 3 can be reduced by means of the braking device 4. The grinding device 1 in Fig. 3 has a switching device 13, which can be actuated by a switching element 14. The release element 10 is mounted in a rocker-like manner about the horizontal axis of rotation H, which runs parallel to the plane E, and can be actuated by actuating the switching element 14, so that the first braking partner 5 of the braking device 4 can be brought out of contact with the second braking partner 6, so that the shaft 3 can rotate unhindered by the braking device 4.Pressing the switching element 14 in the vertical direction can be translated into a vertical movement of one side of the release element 10 by means of the switching device 13, which comprises springs 15 and a fork element 16, whereby another side of the release element 10 can be adjusted in the opposite direction, whereby the brake shoes 11 can be displaced horizontally along the plane E. The springs 15 can restore the rest state of the switching device 13 when the switching element 14 is released, so that the release element 10 can be returned to a rest state so that the braking device 4 can brake the shaft 3.

[0040] Fig. 5 shows a top view of the grinding device 1 with a grinding tool designed as a fly blade 12. The fly blade 12 is attached to the shaft 3 in the container 2, so that the material to be ground in the container 2 can be ground by rotating the shaft 3 and the resulting rotation of the fly blade 12. This can occur, in particular, upon actuation of the switching element 14.

[0041] Fig. 6 and Fig. 7 show plan views of the braking device 4 in a cross-section of the grinding device 1. Two brake shoes 11 are in contact with the braking element 7, which is arranged in a rotationally fixed manner on the shaft 3. The grinding device 1 has the switching element 14, by means of which the release element 10 can be actuated, so that the two brake shoes 11, which are rotatably mounted at one end under a cover 17, can press the brake shoes radially against the braking element 7 when the release element 10 pivots back. Reference numerals

[0042] 1 grinding device

[0043] 2 containers

[0044] 3 Wave

[0045] 4 Braking device

[0046] 5 First braking partner

[0047] 6 Second braking partner

[0048] 7 Brake element

[0049] 8 spring

[0050] 9 brake pad

[0051] 10 release element

[0052] 11 brake shoe

[0053] 12 flail knives

[0054] 13 Switching device

[0055] 14 Switching element

[0056] 15 springs

[0057] 16 Fork element

[0058] 17 Cover

[0059] A angle

[0060] E Level

[0061] D axis of rotation

[0062] H Horizontal axis of rotation

Claims

Claims 1. Grinding device (1) comprising a grinding tool arranged in a container (2) which is rotatable by a drive for comminuting a material to be ground, wherein the drive comprises a motor, a shaft (3) driven by the motor and a braking device (4) by means of which a rotational speed of the shaft (3) can be reduced by contact with the braking device (4), characterized in that the braking device (4) comprises a friction brake.

2. Grinding device (1) according to claim (1), characterized in that the friction brake comprises at least one first braking partner (5) and at least one second braking partner (6).

3. Grinding device (1) according to claim 2, characterized in that the second braking partner (6) comprises a braking element (7) which is connected in a rotationally fixed manner to the shaft (3), wherein a rotational speed of the shaft (3) can be reduced by contact between the braking element (7) and the first braking partner (5).

4. Grinding device (1) according to claim 2 or 3, characterized in that the braking device (4) comprises at least one spring (8) by means of which the first braking partner (5) is pressed radially against the second braking partner (6).

5. Grinding device (1) according to claim 2, 3 or 4, characterized in that the first braking partner (5) comprises at least one brake shoe (11) and / or at least one brake pad (9).

6. Grinding device (1) according to one of the preceding claims, characterized in that the brake pad comprises composite fibers.

7. Grinding device (1) according to one of the preceding claims, characterized in that the grinding tool comprises a fly knife (12).

8. Grinding device (1) according to one of the preceding claims, characterized in that the at least one first braking partner (5) is arranged substantially in a plane (E) which has an angle (A) between 60 degrees and 120 degrees to a vertical axis of rotation (D) of the shaft (3), is arranged to be movable and can press radially at the angle (A) onto the second braking partner (6).

9. Grinding device (1) according to one of the preceding claims, characterized in that the braking device (4) has at least one release element (10) by means of which the at least one first braking partner (5) can be brought out of contact with the at least one second braking partner (6).

10. Grinding device (1) according to one of the preceding claims, characterized in that the grinding tool and / or the shaft (3) is rotatable at a speed of up to 32,000 revolutions per minute.

11. Grinding device (1) according to one of the preceding claims, characterized in that the grinding device (1) comprises a switching device (13) by means of which the friction brake can be released and the motor can be actuated.

12. Grinding device (1) according to claim 9 and 11, characterized in that the switching device (13) comprises at least one switching element (14) by means of which the release element (10) can be actuated in the vertical direction.

13. Coffee machine with a grinding device (1) according to one of the preceding claims.

14. A method for grinding, comprising the following steps: a. introducing material to be ground into a container (2) of a grinding device (1); b. switching on the grinding device (1) so that contact between a first braking partner (5) and a second braking partner (6) of a braking device (4) is broken; c. rotating a shaft (3) and comminuting the material to be ground by rotating a grinding tool in the container (2); d. switching off the grinding device (1) so that the first braking partner (5) is pressed against the second braking partner (6) by a spring (8) and the rotations of the shaft (2) are braked.

15. A method for grinding according to claim 14, characterized in that step d is carried out automatically after a predetermined period of time has elapsed.

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