Ball mill

Abstract

A ball mill (1) on a laboratory scale with a support device (2) rotatably mounted about a central axis (3a), with at least one grinding cup holder (4) for at least one grinding cup, wherein the grinding cup holder (4) is rotatably mounted on the support device (2) and is guided by it about the central axis (3a) and, preferably, the grinding cup holder (4) is rotatably mounted about an offset planetary axis (21) relative to the support device (2), and wherein the grinding cup holder (4) has at least one clamping element (19) for axially clamping the grinding cup in and / or on the grinding cup holder (4), characterized in that a lifting device (30) with at least one lifting element (31) is provided for transmitting a motor-generated and / or manually generated clamping force to the clamping element (19), wherein the lifting element (30) is kinematically decoupled from the rotational movement of the support device (7) and / or the rotational movement of the grinding cup holder (4).

Description

[0001] The invention relates to a laboratory-scale ball mill with a support device mounted so as to be rotatable about a central axis, with at least one grinding bowl holder for at least one grinding bowl, wherein the grinding bowl holder is mounted so as to be rotatable on and / or in the support device and is carried along by it about the central axis and, preferably, the grinding bowl holder is mounted so as to be rotatable about a planetary axis offset to the support device, and wherein the grinding bowl holder has at least one clamping element for axially clamping the grinding bowl in and / or on or against the grinding bowl holder and the clamping element is carried along by the support device about the central axis when the grinding bowl holder rotates. If the grinding bowl holder itself is mounted so as to be rotatable about a planetary axis offset to the support device, then the clamping element is carried along by the grinding bowl holder when the grinding bowl holder rotates.is also arranged to rotate about the planetary axis relative to the carrier device.

[0002] A laboratory ball mill with the features described above is already known from DE 10 2012 009 987 A1. Such laboratory-scale ball mills are used for a wide range of applications, for example, for comminuting and mixing samples and / or for mechanical alloying. Possible embodiments of laboratory ball mills, particularly planetary and centrifugal ball mills, are described in DE 10 2012 009 987 A1.

[0003] In particular, DE 10 2012 009 987 A1 describes a laboratory-scale planetary or centrifugal ball mill in which the grinding container is axially clamped in a rigid cage in order to secure the grinding container in a grinding station for a grinding process. The axial clamping is achieved by means of an eccentric shaft extending transversely to the planetary axis, which is rotatably mounted in a receiving device for the grinding bowl. The eccentric shaft is located below an axially movable clamping base. The clamping base can be clamped upwards against the grinding container by a predefined length by the eccentric shaft in order to clamp the grinding container in the cage axially from below against an upper cross bridge. For example, the eccentric shaft transfers the clamping force to the clamping base by means of needle bearings, with which the eccentric shaft is mounted between a lower base section and the clamping base.The clamping base lifts a pressure plate via a spring assembly, which in turn moves an inserted grinding container against a pressure yoke, which acts as a stop for the grinding bowl lid until axial gaps are eliminated from the system. As the clamping is further tightened, a seal between the grinding bowl and the grinding bowl lid is compressed. Once this seal is compressed to a rigid height stop, the clamping base compresses the disc springs over the remaining clamping travel of the eccentric shaft to create the actual axial clamping force for the grinding container in the rigid cage.

[0004] The motor of a motor drive for adjusting or rotating the eccentric shaft is fixedly mounted on a device housing and does not rotate with the support device. A coupling device is provided to operate the eccentric shaft. When the ball mill is at rest and the grinding container is in a specific rotational orientation, this coupling couples the motor drive to the eccentric shaft so that the eccentric shaft can be operated from outside the support device in the rest state. This eliminates the need for electrical cables to the rotating support device, for example, and even in a mill with multiple grinding stations, only one motor is required.

[0005] The coupling of the known laboratory mill comprises several interacting coupling parts of the motor drive and the eccentric shaft, which are intended to automatically engage with each other in a positive-locking manner when the grinding station is in an insertion or removal position. The coupling device is designed as a slotted coupling, in which a pin running transversely to the eccentric shaft engages in a slot of a drive shaft running coaxially to the eccentric shaft when the grinding station is in the insertion or removal position. When engaged, the eccentric shaft can be rotated via the motor in order to automatically axially clamp the grinding vessel or automatically release the clamping again. A commercially available geared motor can be provided as the motor, which generates a torque on a drive shaft that is transmitted to the eccentric shaft.

[0006] The previously described clamping mechanism of the known laboratory mill provides several clamping elements for axially clamping a grinding bowl. These elements are rotatably mounted on the support device as part of a grinding bowl holder and are guided by the support device around the central axis when the support device is rotated. The eccentric shaft serves as a lifting element and clamping element for raising and lowering the clamping base, the spring assembly, and the pressure plate as additional clamping elements. In the known laboratory mill, the eccentric shaft serves to transmit the force and power of the motor drive to the other clamping elements. However, the structural design of the clamping mechanism is mechanically complex.Due to the cage with rotating eccentric shaft used to secure the grinding container and the additional rotating clamping elements, a large number of rotating masses are involved during the grinding process. This complicates unbalance compensation and can lead to malfunctions during operation of the well-known laboratory mill. A large moving mass of the clamping mechanism results in greater bearing loads and requires the use of correspondingly high-quality, expensive bearing components.

[0007] Furthermore, all clamping forces for axially clamping the grinding bowl within the cage must be absorbed within the cage, which leads to high mechanical stress on the cage structure. Component stress and material fatigue can lead to problems related to locking and opening the cage.

[0008] The connection of the eccentric shaft to the motor drive via a coupling device, required for motorized operation of the eccentric shaft, is also mechanically complex, subject to increased wear, and thus requires intensive maintenance. Coupling requires the support device to be precisely maintained at a specific rotational position. Failure to precisely maintain this rotational position can lead to component distortion in the area of ​​the coupling device, even to a complete blockage of the coupling function, making it impossible to clamp or release the grinding container.

[0009] A further disadvantage is the use of the known clamping mechanism in planetary or centrifugal ball mills with multiple grinding stations. Each grinding bowl holder has a separate clamping arrangement consisting of an eccentric shaft and additional clamping elements. To clamp multiple grinding bowls, it is necessary to move the grinding stations into the insertion and removal positions in order to form the coupling between the motor drive and the eccentric shaft of the respective grinding station, and then to clamp the grinding bowl of the respective grinding station. Clamping multiple grinding bowls is therefore very time-consuming.

[0010] The object of the present invention is to provide a laboratory ball mill of the type mentioned above with a locking and / or unclamping mechanism for at least one grinding bowl in the grinding bowl holder that is more advanced than the prior art. The locking and / or unclamping mechanism enables the transmission and transfer of motor-generated or, if necessary, manually generated clamping forces to the clamping element in a structurally simple manner with high operational reliability, and the clamping forces required for clamping lead to a lower mechanical load on the structure of the grinding bowl holder. The locking and / or unclamping mechanism should thus be low-maintenance and allow the transmission of high clamping forces.In particular, the clamping and / or unclamping mechanism should offer the possibility of clamping the grinding bowls in the grinding bowl holders in planetary and centrifugal ball mills with several grinding stations with little expenditure of time and in a simple and convenient manner for the user.

[0011] The aforementioned objects are achieved by a ball mill having the features of claim 1. Advantageous embodiments of the invention are the subject of the subclaims.

[0012] The ball mill according to the invention comprises a lifting device as part of a clamping and / or unclamping mechanism with at least one lifting element for transmitting a motor-generated and / or manually generated clamping force to the at least one clamping element, wherein the lifting element is kinematically decoupled from the rotational movement of the support device and / or the rotational movement of the grinding bowl holder. Multiple lifting elements can also be provided for transmitting a clamping force to the clamping element. The lifting element is not carried along by the support device during rotation of the support device about the central axis.

[0013] A “lifting element” within the meaning of the invention is preferably a passive component which serves purely to transmit and / or transfer a motor or manual drive force to the clamping element. The drive force can be applied manually or via a motor drive unit. The lifting element is preferably located substantially beneath the grinding bowl holder, more preferably beneath the clamping element, and serves in particular to transmit an axial lifting force to the clamping element. An “axial” lifting force within the meaning of the invention exists when the force vector is at least substantially parallel or coaxial (same axis) to or with a rotational axis of the grinding bowl holder and / or a rotational axis of the clamping element. However, an embodiment is also not excluded in which the lifting element at least also or optionally exclusively horizontal orradial force components are transmitted to the clamping element. The invention is described below purely by way of example and not exhaustively, essentially for the transmission of purely axial lifting forces from the lifting element to the clamping element.

[0014] When transmitting force from the lifting element to the clamping element, the lifting element can lie directly against the clamping element, whereby the force is transmitted via contact surfaces of the lifting element and the clamping element that touch each other.

[0015] Furthermore, the lifting element can be permanently connected to a motor drive. A connection to the motor drive can also be present, in particular, if the support device rotates around the central axis during operation of the ball mill.

[0016] The invention is based on the idea of ​​using a clamping element or lifting element that is at least substantially stationary relative to the support device to transmit the clamping forces required for tightening and / or relaxing the grinding bowl in and / or on the grinding bowl holder, which cooperates with at least one clamping element of the grinding bowl holder that is carried by the support device during operation of the ball mill for tightening and / or relaxing. In the embodiment known from DE 10 2012 009 987 A1, an eccentric shaft that rotates during operation of the ball mill serves to transmit and convey motor-generated clamping forces. Deviating from this, the invention provides at least one lifting element that is kinematically decoupled from the rotary movement of the support device and is stationary during operation of the ball mill.The invention thus permits a structural design of the locking and / or unclamping mechanism for the grinding bowl that is characterized by a smaller number of components that are carried around the central axis by the support device during operation of the ball mill. Lower rotating masses enable a simple structural design that is low in wear and thus requires little maintenance. Furthermore, the invention permits a structural design of the locking and / or unclamping mechanism in which clamping forces are absorbed by the grinding bowl holder, in particular, with lower mechanical loads. Furthermore, the locking and / or unclamping mechanism can provide for the transmission of motor-generated clamping forces from a motor to the clamping element without the need for a clutch, thus avoiding the disadvantages associated with the use of a clutch device in the ball mill known from DE 10 2012 009 987 A1.

[0017] The grinding bowl holder is designed, in particular, exclusively for the underside or bottom-side mounting of the grinding bowl and / or is axially adjustable for axially and / or radially clamping a grinding bowl on or against the grinding bowl holder and / or for axially and / or radially relaxing the grinding bowl. This enables user-friendly fastening of the grinding bowl to, in, on, and / or with the grinding bowl holder. Compared to the design of the grinding bowl holder known from DE 10 2012 009 987 A1 as a side-loading cage, the invention provides the possibility of faster changing of the grinding bowl and / or rapid access to the grinding bowl interior by removing the grinding bowl cover.

[0018] A particularly simple structural embodiment of the invention provides that the lifting element is guided and / or mounted in a height-adjustable manner, in particular only substantially parallel and / or coaxial with a longitudinal or rotational axis of the grinding bowl holder, the grinding bowl and / or the clamping element, preferably in an at least substantially vertical direction. The lifting force is then preferably transferred to the clamping element only by adjusting the height of the lifting element when they come into contact. In this context, the lifting element can be designed, for example, as a lifting block, which can be adjusted in height in the axial direction, preferably in an at least substantially vertical direction, via an adjusting or actuating element.

[0019] Alternatively, an embodiment can also be provided in which the lifting element as such is adjustably guided and / or mounted transversely to the rotational axis of the grinding bowl holder and / or the clamping element. In this embodiment, the lifting element can be designed, for example, as a push rod with an inclined run-on surface. The run-on surface is brought into contact with the clamping element during the adjustment movement of the push rod to transmit clamping forces, and the clamping element is raised or lowered during the adjustment movement depending on the direction of movement.

[0020] In a further alternative embodiment, the lifting element can also be designed as an eccentric shaft that is arranged to rotate transversely to the longitudinal or rotational axis of the grinding bowl holder and / or the clamping element, wherein an eccentric section of the eccentric shaft comes into contact with the clamping element to transmit the required clamping force. At this point, the invention takes up the use of an eccentric shaft for transmitting clamping forces known from DE 10 2012 009 987 A1. However, in contrast to the known ball mill, the invention proposes a stationary arrangement of the eccentric shaft, in which the eccentric shaft is kinematically decoupled from the rotational movement of the support device and / or the rotational movement of the grinding bowl holder.

[0021] Finally, a "lifting element" within the meaning of the invention can also be an actuator or a linear motor that moves a force transmission element, preferably in an at least substantially vertical direction, against the clamping element, thus transmitting the required force for raising or lowering to the clamping element. For this purpose, the actuator or linear motor can be arranged below the clamping element.

[0022] It is expedient if the axial lifting force can be transmitted by the lifting element only when a specific insertion and / or removal position of the support device is reached, i.e., when a specific insertion and / or removal position of the grinding bowl holder is reached, i.e., when a specific rotational orientation of the support device is reached. The specific insertion and / or removal position is preferably reached when the clamping element is located coaxially above the lifting element.

[0023] When the grinding bowl is properly clamped to and / or in the grinding bowl holder, the lifting element is preferably spaced apart from the clamping element, allowing relative movement between the clamping element and thus the grinding bowl holder on the one hand, and the lifting element on the other hand, in the circumferential direction of the circular path along which the grinding bowl holder is moved during operation of the ball mill. The lifting element is then mechanically decoupled from the clamping element; in particular, there is no direct physical connection between the two components.

[0024] If the grinding bowl is not inserted or is inserted incorrectly, the invention allows the clamping element to be lowered or lowered relative to the lifting element in such a way that a positive and / or non-positive connection is formed between the clamping element and the lifting element. The lifting element is then mechanically coupled and / or can be coupled to the clamping element and can perform a braking or stopping function for the support device and / or the grinding bowl holder if the grinding bowl is not properly held on and / or in the grinding bowl holder.

[0025] To transmit a motor and / or manual drive force to the lifting element and for adjustment, in particular for lifting the lifting element, the lifting device can have at least one adjustment element. The adjustment element is then also kinematically decoupled from the rotational movement of the support device and / or the rotational movement of the grinding bowl holder. Particularly preferably, an adjustment movement of the adjustment element transverse to the longitudinal axis or rotational axis of the grinding bowl holder and / or the clamping element can lead to an adjustment movement of the lifting element. In this context, the adjustment element can be designed as a spindle or push rod, wherein the motor drive force of a drive motor is transmitted to the spindle or push rod, if necessary via a motor coupling, and the lifting element is adjusted, preferably raised, by axial adjustment of the spindle or push rod.This enables a structurally simple transmission of high clamping forces.

[0026] An eccentric shaft arranged rotatably relative to the lifting element can also be provided as an adjusting element, which acts against the lifting element, wherein the lifting element can be lifted via an eccentric section of the eccentric shaft.

[0027] Finally, a lever can also be provided as an adjusting element in order to adjust, in particular to lift, at least one lifting element for transmitting clamping forces with a reduced expenditure of force.

[0028] The adjusting element can be permanently mechanically connected to a motor drive, in particular without a coupling, i.e. in particular during rotation of the support device or operation of the ball mill. A coupling device can also be provided for the rigid, elastic, movable or detachable connection of the adjusting element to a motor drive. The motor drive can preferably be arranged laterally spaced from rotating components and / or vertically below the grinding bowl holder. The drive is further preferably arranged in a stationary manner and kinematically decoupled from the rotational movement of the support device and / or the rotational movement of the grinding bowl holder. In principle, manual actuation of the adjusting element using an adjusting tool or an adjusting handle is also possible.

[0029] Further expediently, at least one coupling element is provided for the kinematic coupling of the adjustment element to the lifting element, wherein, preferably, the coupling element can be adjusted by rotating the adjustment element relative to the adjustment element. The coupling element can, for example, be wedge-shaped with inclined and / or curved contact surfaces. These come into contact with the lifting element during the translational movement of the adjustment element, which can lead to the lifting element being lifted. A sliding or rolling contact can reduce frictional forces and enable a low-force coupling of the movement of the adjustment element to the lifting element via the coupling element. A low-friction coating and / or a hardened contact surface of the coupling element also simplify the kinematic coupling. A corresponding contact surface can also be provided on the lifting element.Particularly preferably, the lifting element can rest against an inclined or curved run-up surface on the coupling element via at least one roller, which rolls up or down along the run-up surface during the lifting movement of the lifting element.

[0030] Preferably, the coupling element is a separate component. However, an embodiment in which the adjusting element acts directly, i.e., immediately, against or rests against the lifting element and, for example, has an inclined contact surface that comes into active contact with the lifting element during the adjusting movement of the adjusting element and, for example, lifts the lifting element to transmit the clamping force is not excluded.

[0031] Preferably, however, the coupling element is adjustably guided on the adjustment element. In this context, the adjustment element can be designed as a spindle with an external thread, and the coupling element can have a threaded bore for a threaded portion of the spindle. If the coupling element is only adjustable in a linear direction, then, depending on the thread pitch, rotation of the threaded spindle results in an adjustment movement of the coupling element along the spindle's rotational axis.

[0032] The coupling element is also kinematically decoupled from the rotational movement of the carrier device and / or the rotational movement of the grinding bowl holder.

[0033] The lifting device can further comprise at least one lifting housing, wherein the lifting element is guided and / or mounted in the lifting housing, preferably in a height-adjustable manner and, more preferably, with lateral play. The lifting housing can have a recess for the lifting element, in which the lifting element is received, preferably in an axially height-adjustable manner. It is expedient if the lifting element is received and guided loosely, i.e., not tightly, in the recess. This allows a lifting movement of the lifting element in the recess without the risk of jamming the lifting element.

[0034] It is advantageous if the lifting housing is also kinematically decoupled from the rotational movement of the support device and / or the rotational movement of the grinding jar holder. As part of the lifting device, the lifting housing is then not carried along by the support device during its rotational movement around its center axis.

[0035] In order to keep component loads to a minimum, in particular on bearings of the support device and / or the grinding bowl holder, at least one abutment or support section can be provided on the lifting housing to form an abutment for the grinding bowl holder. For this purpose, the grinding bowl holder can have a holding section corresponding to the abutment section on the lifting housing. The formation of an abutment requires the abutment section to come into contact with the holding section. The formation of an abutment can in particular occur before the lifting element comes into contact with the clamping element, simultaneously with it, or only afterwards. However, the clamping element is preferably lifted only after the holding section on the grinding bowl holder rests against the abutment section on the lifting housing.

[0036] In particular, the abutment for the grinding bowl holder ensures that the lifting housing is held against the grinding bowl holder during the transmission of clamping forces, and that the compressive forces transmitted from the lifting element to the clamping element and the opposing forces at the abutment essentially compensate each other. The lifting housing is essentially not supported by the floor of the mill, so that the clamping and unclamping forces essentially do not need to be transmitted via the bearing means of the support device and the grinding bowl holder. In particular, when lifting the lifting element, essentially no vertical forces need to be absorbed by the adjustment element.

[0037] The holding section on the grinding bowl holder can engage below and / or behind the abutment section on the lifting housing to form an abutment. Alternatively, it is possible for the abutment section on the lifting housing to engage below and / or behind a corresponding holding section on the grinding bowl holder. The abutment section on the grinding bowl holder can be formed in a particularly advantageous manner at the lower end of a planetary shaft of the grinding bowl holder, for example as a radially outwardly projecting shoulder. An armature-shaped or piston-shaped clamping element can be guided in the planetary shaft so as to be axially or vertically adjustable. A recess can be provided on the lifting housing, on which radially inwardly projecting projections are formed, which form the abutment section on the lifting housing.

[0038] In order to form the abutment or to ensure contact between an abutment section on the lifting housing and a holding section on the grinding bowl holder, in particular on a planetary shaft of the grinding bowl holder, the lifting housing can be adjustable, in particular height-adjustable, relative to the grinding bowl holder to form the abutment. It is expedient if the formation of the abutment is linked to achieving a specific rotational orientation of the support device intended for inserting / removing a grinding bowl. Furthermore, when adjusting the height of the lifting housing, a corresponding height adjustability of the adjusting means and, if appropriate, a drive connected to the adjusting means is preferably provided.

[0039] During rotation of the support device about the central axis or during operation of the ball mill according to the invention, a structural design of the locking and / or unclamping mechanism can be provided such that the grinding bowl holder is carried along by the support device and is moved freely past and / or in regions in the lifting housing.

[0040] If the holding section is formed at a lower end of a planetary axle body, in which the clamping element can be guided in a height-adjustable manner, the planetary axle body can engage with a lower end facing the lifting housing into a corresponding recess in the lifting housing and periodically pass through the recess during the rotational movement of the carrier device. For this purpose, the recess can be open on both sides in the circumferential direction of the carrier device so that a collision of the components cannot occur when the planetary axle body passes through the lifting housing with its lower end. The holding and abutment geometries on the grinding bowl holder on the one hand and the lifting housing on the other must be designed accordingly.In order to be able to reliably rule out collisions between the grinding bowl holder, in particular an axle body of the grinding bowl holder, and the lifting housing, abutment sections can be formed on the lifting housing, for example, which extend only over a part of the width of the recess and / or over a part of the circumferential length of the recess and are further preferably arranged opposite one another.

[0041] In a preferred embodiment of the invention, the lifting housing can preferably only be arranged so as to be height-adjustable relative to the grinding bowl holder and / or an axle body of the grinding bowl holder and can be arranged in a fixed position in a direction transverse to the rotation axis of the grinding bowl holder and / or transverse to the rotation axis of the clamping element or transverse to the rotation axis of the carrier device.

[0042] If a coupling element is provided for transmitting force to the lifting element, the coupling element can be adjustably guided in and / or on the lifting housing and, preferably, can be moved during an adjustment movement relative to the lifting housing in a direction transverse to the rotation axis of the grinding bowl holder and / or to the rotation axis of the clamping element.

[0043] The coupling element can be guided in and / or on the lifting housing via rollers. Sliding contact is also possible. To reliably prevent the coupling element from jamming during the adjustment movement in the lifting housing, the lifting housing has a corresponding guide recess for the coupling element, in which the coupling element is guided with play, preferably loosely and not tightly. Furthermore, in particular, rotationally fixed guidance of the coupling element in the lifting housing is ensured by appropriate guide geometries on the lifting housing and / or on the coupling element. When the coupling element is actuated via a spindle, the coupling element then only undergoes an adjustment movement relative to the lifting housing in the longitudinal direction of the spindle.

[0044] The coupling element can preferably be raised or lowered together with the lifting housing. The raising or lowering of the lifting housing is preferably achieved by an adjusting movement of the coupling element or by moving the coupling element relative to the adjusting element.

[0045] If, for example, a threaded spindle is provided as the adjusting element, wherein the coupling element, which is provided with a threaded bore and penetrated by the threaded spindle, is guided in the lifting housing so that it can be moved or adjusted in only one direction, the movement of the coupling element by rotating the threaded spindle along the spindle axis can result in the positively guided lifting or lowering of the coupling element and thus also of the lifting housing.

[0046] For example, the lifting device can have a preferably stationary support element for the coupling element, on which the coupling element rests and relative to which the coupling element is adjusted with the aid of the adjustment element. The support element can provide at least two different height levels for the coupling element, wherein the coupling element is adjusted with the adjustment element and, during the adjustment, slides together with the lifting housing from a first height level to a second height level. The adjustment movement of the coupling element with the adjustment element then automatically results in a change in the height of the coupling element and the adjustment element, and thus also in a change in the height of the lifting housing.

[0047] By means of the lifting device provided according to the invention with a lifting element that is kinematically decoupled from the rotary movement of the carrier device and / or the rotary movement of the grinding bowl holder, the lifting device can be designed for the synchronous lifting and / or lowering of several clamping elements. For this purpose, an adjusting element can be provided, the adjustment of which leads to the actuation, in particular to the lifting, of several lifting elements and thus to the synchronous lifting and / or lowering of the clamping elements of several grinding stations. For example, a threaded spindle can be provided, on which two coupling elements are guided so as to be movable in the axial direction. Each coupling element interacts with a lifting element, wherein the adjusting movement of the spindle, ieRotation of the spindle around the rotation axis leads to simultaneous contact between the coupling elements and the lifting elements, whereupon the lifting elements in turn come into contact with the clamping elements of two grinding bowl holders and can actuate, in particular lift, the clamping elements. If the adjusting element is designed as a threaded spindle and the coupling elements are guided on the threaded spindle so that they can be adjusted in the axial direction, the coupling elements can have threaded holes and, accordingly, the threaded spindle can have external thread sections with different directions of rotation, so that a rotational movement of the threaded spindle results in an adjustment movement of the two coupling elements in opposite directions.For example, a spindle with a left-hand and a right-hand external thread section can be used as an adjustment element together with coupling elements that have corresponding internal threaded holes with different directions of rotation. The two coupling elements can then easily adjust two lifting elements simultaneously, in particular raising or lowering them, which in turn act against clamping elements of two grinding stations.

[0048] A preferred embodiment of the mill according to the invention has at least two grinding bowl holders and at least two clamping devices, each with a clamping element for axially holding or clamping a respective grinding bowl on or against the respective grinding bowl holder and / or in the respective grinding bowl holder and / or for axially relaxing the tension, in particular wherein the common lifting device is provided for the simultaneous and / or synchronous raising and / or lowering of several, preferably all, clamping elements. However, it is not excluded that several adjustment elements can be provided in order to be able to adjust several coupling elements independently of one another if necessary. The threads can also be designed in the same direction, so that both coupling elements are adjusted in the same direction when the adjustment element is adjusted.

[0049] It is understood that the features of the embodiments of the invention described above and illustrated and described below with reference to the drawings, regardless of the paragraph formatting chosen, jointly or individually define essential components of the invention, in particular even when they are described together with other features.

[0050] The invention will be explained in more detail below using an exemplary embodiment with reference to the figures. Fig. 1 a perspective view of a ball mill according to the invention with two grinding bowl holders, Fig. 2 a top view of the ball mill from Fig. 1, Fig. 3 a partial sectional view of the ball mill from Fig. 1 along the section line III-III from Fig. 2, where the grinding bowl holders are shown in a clamped state, Fig. 4 a partial sectional view of the ball mill from Fig. 1, which shows the right grinding bowl holder and part of a lifting device for the grinding bowl holder in a relaxed state of the grinding bowl holder, Fig. 5 a sectional view of the ball mill from Fig. 1 along the section line VV from Fig. 2 and Fig. 6 the detail VI from Fig. 5 in an enlarged view.

[0051] In the Fig. 1 to 6 show a laboratory-scale ball mill 1 comprising a support device 2 rotatably mounted about a central axis 3 and rotating about the central axis 3a during operation of the mill 1. In the exemplary embodiment, the ball mill 1 comprises two grinding bowl holders 4, each grinding bowl holder 4 being designed to secure a grinding bowl (not shown) for a grinding operation of the ball mill 1. The grinding bowls can, for example, have a size between 100 ml and 500 ml.

[0052] Each grinding bowl holder 4 is rotatably mounted on the support device 2 and is guided by the support device during rotation about the central axis 3a. Furthermore, each grinding bowl holder 4 has a planetary axle body 5 and is rotatably mounted relative to the support device 2.

[0053] The two grinding bowl holders 4 are positioned opposite one another with respect to the central axis 3a, so that their moment of inertia compensates for each other and their mass generates the smallest possible imbalance when rotating around the central axis 3a. However, the features described below using the example of a ball mill 1 with multiple grinding stations can also be implemented in the same way in laboratory ball mills with only one grinding station or with more than two grinding stations.

[0054] A drive motor 6, by means of a V-belt 7 via a pulley 8, sets the support device 2 in rotation about the central axis 3a, whereby the grinding cup holders 4 with a cover plate 9 of the support device 2 rotate on a circular path around the central axis 3a. The cover plate 9 is in the Fig. 3 and Fig. 4 not shown.

[0055] A toothed belt drive 10 coupled to the belt drive of the pulley 8 also causes the grinding bowl holders 4 to rotate around the planetary axes 21, which are mounted eccentrically to the center axis 3a. The grinding stations thus rotate around the center or sun axis 3a and simultaneously rotate around their own planetary axis 21. The directions of rotation can be opposite.

[0056] The central axle body 3 is rigidly connected to a base plate 11, which in turn is attached to a housing base plate 12. The support device 2 is rotatably mounted on the stationary central axle body 3 by means of ball bearings 13, 14.

[0057] The coupled belt drive 10 comprises toothed belt wheels 15, 16 to drive the rotation of the grinding bowl holders 4 with two further toothed belts 17, 18.

[0058] As can be seen in particular from the Fig. 3 and Fig. 4, each grinding bowl holder 4 has a piston-like clamping element 19 for axially clamping a grinding bowl to a grinding bowl receptacle 20. The clamping element 19 is axially displaceably received in the planetary axle body 5. During the self-rotation of the grinding bowl holders 4, the planetary axle bodies 5 rotate about their planetary axes 21, wherein the planetary axle bodies 5 are rotatably mounted by means of ball bearings 22, 23 on a block-like reinforced bearing area 24 of the pulley 8 on the one hand and on a disk-like bearing block 25 which is firmly connected to the pulley 8.

[0059] The clamping and unclamping of a grinding bowl on a grinding bowl holder 4 is carried out as described below. Fig. 3 shows the grinding bowl holders 4 in the clamped state, in which, when the grinding bowl base of a grinding bowl is properly placed on the grinding bowl holder 20, clamping stones 26 are pushed radially outwards into a corresponding holding projection on the grinding bowl base by a pressure plate 27, so that the grinding bowl is fixed to the grinding bowl holder 20. The pressure plate 27 is firmly connected to the clamping element 19 in the axial direction, wherein the clamping element 19 is spring-loaded. Two disc springs 28 press the clamping element 19 and thus the pressure plate 27 away from the grinding bowl holder 20 in a vertical direction downwards, which, when the grinding bowl is placed on the grinding bowl holder 20, leads to clamping of the grinding bowl via the outward-projecting clamping stones 26. For relaxing the tension on the grinding bowl orIn order to remove the grinding bowl from the grinding bowl holder 20, it is necessary to lift the clamping element 19 vertically upwards against the spring force of the disc springs 28, so that the pressure plate 27 is also lifted and the clamping blocks 26 are pulled radially inward by another spring means 29. This causes the clamping blocks 26 to emerge from a groove-shaped receptacle on the grinding bowl base, so that the grinding bowl is released and can be removed from the pressure plate 27.

[0060] Fig. 4 shows an example of a grinding bowl holder 4 in a relaxed state when the clamping element 19 and thus the pressure plate 27 are raised and the clamping stones 26 are pulled radially inwards.

[0061] To apply a lifting force required to lift the clamping element 19 from the clamped state to the relaxed state, the ball mill 1 has a lifting device 30. The lifting device 30 and the principle of force transmission to the clamping element 19 are explained below using the example of the Fig. 1 to 6, and the clamping of the grinding bowl via the grinding bowl base on the grinding bowl receptacle 20 via clamping blocks 26, as shown and described, are described. It is understood that the clamping and unclamping mechanism shown and described has been selected as an example to explain the transmission of clamping forces or lifting forces to a clamping element of a grinding bowl holder. The lifting device 30 described below can, if required, also be used to lift clamping elements in grinding bowl holders 4 that are structurally designed differently from the illustrated embodiment, in order to transmit axial and / or vertical clamping forces to at least one clamping element of a grinding bowl holder.

[0062] The lifting device 30 has a lifting element 31, which is guided in a lifting housing 32 coaxially with the clamping element 19. The lifting element 31 rests freely or loosely in a recess of the lifting housing and is freely movable in the axial direction of the clamping element 19.

[0063] The lifting element 31 rests against a lifting wedge as a coupling element 34 via two rollers 33. The rollers 33 are connected via a retaining pin 33a. Centrally between the two rollers 33, the lifting element 31 is held on the retaining pin 33a via a hole in the lifting element 31.

[0064] The lifting wedge kinematically couples the lifting element 31 with an adjusting element 35 designed as a threaded spindle on both sides. The coupling element 34 has a through-bore with an internal thread and is guided in the lifting housing 32 so as to be displaceable in the axial direction of the adjusting element 35 and rests on two adjacent pairs of rollers 36. Each pair of rollers 36 is mounted on the lifting housing 32 via a bearing pin 37. This results in particular from Fig. 6, which shows, in a sectional view, lateral projections 38 in the base area of ​​the coupling element 34, which engage below and behind lateral shoulders 39 on the inner sides of the lifting housing 32. The coupling element 34 is guided via the shoulders 39 so that it can be displaced in the axial direction of the adjusting element 35 and is fixed transversely to the axial direction.

[0065] Fig. 4 shows the relaxed state of the grinding bowl holder 20 with the clamping element 19 raised. Due to the threaded guide of the coupling element 34 on the adjusting element 35, a rotation of the adjusting element 35 about its rotation axis in the direction of movement 40, depending on the direction of rotation of the threaded spindle, results in a corresponding adjusting movement of the coupling element 34. Since the lifting element 31 is guided via the rollers 33 on an inclined run-on surface 41 of the coupling element 34, an adjusting movement of the coupling element 34 according to Fig. 4 to the right or left results in a corresponding upward or downward movement of the lifting element 31 in the longitudinal direction of the clamping element 19, so that the clamping element 19 is raised or lowered, respectively. When the clamping element 19 is raised, as described above, this leads to the lifting of the pressure plate 27, whereupon the clamping blocks 26 are pulled radially inward, and a grinding bowl resting on the grinding bowl holder 20 with a base is released.

[0066] The lifting device 30 with the lifting housing 32 and the lifting element 31 guided on the lifting housing 32, as well as the coupling element 34 also guided on the lifting housing 32, and the adjusting element 35 designed as a threaded spindle are kinematically decoupled from the support device 2 or the rotational movement of the pulley 8 and all components connected to the pulley 8 about the center axis 3a. In other words, this means that the lifting device 30 is not driven by the support device 2 about the center axis 3a during operation of the ball mill 1.

[0067] An adjustment motor 42, which can be a commercially available gear motor, is provided to drive the adjustment element 35. The adjustment motor 42 transmits a torque to the adjustment element 35, which is converted into a movement of the lifting element 31 via the coupling element 34. The adjustment motor 42 is mounted in such a way that it can follow an adjustment movement, in particular a height adjustment, of the adjustment element 35.

[0068] As can be seen in particular from Fig. 4, the lifting housing 32 has lateral abutment sections 43 in the upper area. The planetary axle body 5 has a diameter extension at the lower end, which forms a circumferential holding section 44 that engages below and behind the abutment sections 43. However, in a direction transverse to the longitudinal axis of the clamping element 19 or the planetary axis 21 or the center axis 3a, the lifting housing 32 is open. This results in a recess in the lifting element 31 for the lower end of the planetary axle body 5, which is open in the circumferential direction of the circular path along which the planetary axle body 5 is moved during the rotation of the carrier device 2.

[0069] Fig. 4 shows the grinding bowl holder 20 in the relaxed state, when the clamping element 19 is lifted by the lifting element 31. Here, the holding section 44 at the lower end of the planetary axle body 5 rests from the inside against the abutment sections 43 of the lifting housing 32 to form an abutment when the grinding bowl holder 4 is transferred from a clamped state to a relaxed state.

[0070] To form the abutment, the lifting housing 32 can be adjusted or lowered vertically relative to the grinding bowl holder 4 or relative to the planetary axle body 5. The lowering of the lifting housing 32 is coupled to the achievement of a specific rotational orientation of the support device 2, in which the clamping element 19 is arranged above the lifting element 31. Due to the possibility of raising and lowering the lifting housing 32 as needed, the planetary axle body 5 can be carried by the support device 2 around the central axis 3 during the rotation of the support device 2, i.e. during the grinding operation of the ball mill 1, and can be guided freely past the abutment sections 43 of the lifting housing 32. Before or simultaneously with the raising of the lifting element 31, the abutment is formed by lowering the lifting housing 32.

[0071] The lifting housing 32 is raised and lowered via a lifting bar 46, which is preferably firmly connected to the housing base plate 12 and has a shoulder 47 which ends in a bevel 48. The coupling element 34 has a bevel 49 on the underside and, in the clamped state of the grinding bowl holder 4 when the lifting housing 32 is raised, rests with its underside on the shoulder 47. This is shown in Fig. 3. When adjusting the coupling element 44 according to Fig. 3 to the right, i.e. when lifting the lifting element 31, the coupling element 34 slides downwards over the corresponding slopes 48, 49, which leads to a vertical lowering of the lifting housing 32 with the abutment sections 43 and to the formation of the abutment according to Fig. 3. As a result, when the lifting element 31 is lifted, the lifting housing 32 is only supported against the planetary axle body 5, which leads to a very low load, in particular on the bearing components.

[0072] As can be seen from Fig. 3, the lifting device 30 is designed for the synchronous raising or lowering of the clamping elements 19 of the opposing grinding bowl holders 4 and, for this purpose, has, in particular, two coupling elements 34, two lifting housings 32, two lifting elements 31, and a threaded spindle as an adjusting element 35, which has a left-hand thread section and a right-hand thread section. Due to an opposite inclination of the contact surfaces 41 and correspondingly different thread directions, rotation of the threaded spindle provided as an adjusting element 35 causes the coupling elements 34 of the two lifting devices 30 to move towards or away from each other, which leads to the simultaneous raising or lowering of the lifting elements 31.

[0073] The retaining bolt 33a is vertically tensioned by a spring means 50, preferably an annular spring, which is wound around the retaining bolt 33a and the two bearing bolts 37, so that it always experiences a downward spring force in addition to the weight force in order to always be in contact with the coupling element 34 via the rollers 33. This avoids the risk of the retaining bolt 33a with the rollers 33 and the lifting element 31 remaining in the upper position due to only minimal jamming, even though the coupling element 34 is not currently lifting it. List of reference symbols: 1 ball mill 2 carrier device 3 central axle body 3a Center axis 4 grinding bowl holder 5 planetary axle bodies 6 Drive motor 7 V-belts 8 pulley 9 Cover plate 10 Toothed belt drive 11 Base plate 12 Housing base plate 13 ball bearings 14 ball bearings 15 Timing belt pulley 16 Timing belt wheel 17 Timing belt 18 timing belts 19 clamping element 20 grinding bowl holder 21 Planetary axis 22 ball bearings 23 ball bearings 24 storage area 25 bearing block 26 terminal block 27 printing plate 28 disc spring 29 spring means 30 lifting device 31 lifting element 32 lifting housing 33 roll 33a retaining bolt 34 coupling element 35 Adjustment element 36 pairs of rollers 37 bearing bolts 38 lead 39 shoulder 40 Direction of movement 41 Ramp surface 42 Adjustment motor 43 abutment section 44 stopping section 45 recess 46 Lifting bar 47 paragraph 48 slopes 49 slopes 50 spring products

Claims

[1] Ball mill (1) on a laboratory scale with a support device (2) rotatably mounted about a central axis (3a), with at least one grinding bowl holder (4) for at least one grinding bowl, wherein the grinding bowl holder (4) is rotatably mounted on the support device (2) and is carried by it about the central axis (3a) and, preferably, the grinding bowl holder (4) is rotatably mounted about an offset planetary axis (21) to the support device (2), and wherein the grinding bowl holder (4) has at least one clamping element (19) for axially clamping the grinding bowl in and / or on the grinding bowl holder (4), characterized by that a lifting device (30) with at least one lifting element (31) is provided for transmitting a motor-generated and / or manually generated clamping force to the clamping element (19), wherein the lifting element (30) is kinematically decoupled from the rotational movement of the carrier device (7) and / or the rotational movement of the grinding bowl holder (4). [2] Ball mill (1) according to claim 1, characterized by that the lifting device (30) has at least one adjusting element (35) for adjusting, in particular for lifting, the lifting element (31) and for transmitting a motor and / or manual drive force to the lifting element (31). [3] Ball mill (1) according to claim 1 or 2, characterized by that the adjusting element (35) is kinematically decoupled from the rotational movement of the carrier device (2) and / or the rotational movement of the grinding bowl holder (4). [4] Ball mill (1) according to one of the preceding claims, characterized bythat at least one coupling element (34) is provided for the kinematic coupling of the adjusting element (35) to the lifting element (31), wherein, preferably, the coupling element (34) is adjusted by rotation of the adjusting element (35) relative to the adjusting element (35), and that the coupling element (34) is kinematically decoupled from the rotational movement of the carrier device (2) and / or the rotational movement of the grinding bowl holder (4). [5] Ball mill (1) according to one of the preceding claims, characterized by that the lifting device (30) has at least one lifting housing (32) and that the lifting element (31) is guided and / or mounted in the lifting housing (32), preferably height-adjustable and, more preferably, with lateral play. [6] Ball mill (6) according to one of the preceding claims, characterized by that the lifting housing (32) is kinematically decoupled from the rotational movement of the carrier device (2) and / or the rotational movement of the grinding bowl holder (4) [7] Ball mill (1) according to one of the preceding claims, characterized by that at least one abutment section (43) is provided on the lifting housing (32) to form an abutment for the grinding bowl holder (4). [8] Ball mill (1) according to one of the preceding claims, characterized by that the coupling element (34) is adjustably guided in and / or on the lifting housing (32), preferably relative to the lifting housing (32) in a direction transverse to the planetary axis (21) of the grinding bowl holder (4) and / or the clamping element (19). [9] Ball mill (1) according to one of the preceding claims, characterized by that the coupling element (34) can be raised or lowered together with the lifting housing (32), wherein, preferably, the raising or lowering is effected by an adjusting movement of the coupling element (34) relative to the adjusting element (35). [10] Ball mill (1) according to one of the preceding claims, characterized bythat the lifting device (30) is designed for the synchronous lifting and / or lowering of several clamping elements (19).

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