Lining apparatus

Abstract

The present disclosure relates to a method for positioning a wear element with respect to a support structure using a multi-axis wear element positioning apparatus having a wear element positioning unit. The method comprises the steps of: arranging the wear element positioning apparatus in a replacement position with respect to the support structure; defining coordinates of an intersection (203) of a virtual line (Qg) with a surface of the support structure; aligning the wear element positioning unit with the surface of the support structure at the intersection (203) such that a connection surface of a wear element carried by the wear element positioning unit matches a corresponding connection surface of the support structure at the intersection (203). The present disclosure also relates to a system for positioning a wear element with respect to a support structure.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a system and method for positioning a wear element relative to a support structure. The system comprises a multi-axis wear element positioning device having a wear element positioning unit for positioning a wear element relative to a support structure. BACKGROUND

[0002] In many applications, it is required to periodically replace a wear or broken wear element before the underlying support structure is damaged. Typically, such wear elements have a considerable size and weight and cannot be handled manually, so different types of positioning devices are used to carry the wear element and position it adjacent to the support structure so that the wear element can be fastened to the support structure by means of bolting or the like. Even though such devices eliminate the need for an operator to lift and carry heavy equipment and components, the requirements for the operation of the positioning device are still high since such positioning devices typically need to be operated with up to seven or more degrees of freedom. Manually operating all degrees of freedom is a challenging task and requires a lot of operator skill. Therefore, correctly operating the machine to align the wear element with the support structure is a common cause of lost time.

[0003] In order to be able to reduce the time required for replacing such wear elements, one type of prior art device comprises a solution using sensors that provide visual feedback to the operator about the alignment situation. However, this solution still requires the operator to have sufficient skill to respond to the feedback and manipulate the wear element positioning unit accordingly, so the positioning of the wear element still takes a considerable amount of time. SUMMARY

[0004] It is an object to alleviate, mitigate or eliminate one or more of the above-mentioned drawbacks and disadvantages in the art, either individually or in any combination, and to address at least the above-mentioned problems. According to a first aspect, there is provided a system for positioning a wear element relative to a support structure. The system comprises a multi-axis wear element positioning device having a wear element positioning unit, wherein the wear element positioning device is arrangeable in a replacement position relative to the support structure. The system further comprises a processing arrangement arranged to determine coordinates of an intersection of a virtual line originating from the multi-axis wear element positioning device with a surface of the support structure. The processing arrangement is further arranged to automatically determine an orientation of the wear element positioning unit in which the wear element positioning unit is aligned with the surface of the support structure at the intersection such that a connection surface of a wear element carried by the wear element positioning unit matches a corresponding connection surface of the support structure at the intersection. The processing arrangement is configured to control an alignment device to orient the wear element positioning unit accordingly.

[0005] The system can be advantageous in that it avoids the need for an operator to perform a complete, actual alignment procedure. Instead, such a system is itself configured to perform at least part of the alignment based on calculations made in the processing device. This can save a significant amount of time during replacement of a wear element. This is because the final adjustment before placing the wear element at the support structure is in fact the most complex. At this point, while adjusting the orientation of the wear element, all available degrees of freedom of the multi-axis wear element positioning device are needed to move the wear element towards the support structure so that the respective surfaces of the wear element and the support structure match each other. The adjustment of the orientation of the wear element is particularly time-consuming and, given the large number of wear elements that are replaced, can make the downtime of, for example, a grinding machine, quite long.

[0006] According to some embodiments, the virtual line originates from the multi-axis wear element positioning device.

[0007] According to some embodiments, the virtual line is defined by a pointing direction of the wear element positioning unit.

[0008] According to some embodiments, the virtual line originates from a point of attachment of the wear element positioning unit to the multi-axis wear element positioning device. This makes it easy for an operator to direct the wear element positioning unit towards a desired position on the support structure.

[0009] According to some embodiments, the yaw angle, the roll angle and the pitch angle of the wear element positioning unit can be adjusted by the alignment device. This is advantageous in that the wear element can be aligned by movements at the wear element positioning unit (also referred to as a grabber or grabber head) only. By adjusting these three degrees of freedom, the wear element can be correctly oriented with respect to the surface of the support structure.

[0010] According to some embodiments, the wear element positioning unit is arranged on a telescoping crane. The telescoping crane is able to provide the required load capacity and sufficient range for all components that need to have a wear element replaced.

[0011] According to some embodiments, the yaw angle of the wear element positioning unit can be adjusted by an operator. By adjusting the yaw of the wear element positioning unit, the direction of the virtual line can be adjusted.

[0012] According to some embodiments, the slew angle, the luff angle and the telescopic extension of the telescoping crane can be adjusted by an operator. Similar to the yaw, these can be used by an operator to adjust the direction of the virtual line and, thus, the position of the intersection at the support structure. They can be used individually or in any combination thereof.

[0013] According to some embodiments, the common coordinate system of the multi-axial wear element positioning device and the support structure emanates from the origin of the telescopic crane. Since the crane can be set in a fixed and known position relative to the support structure, the position of the origin of the common coordinate system relative to the support structure is also always known. Based on this and the structural dimensions of the multi-axial wear element positioning device and the support structure, the position of the wear element can be defined in this coordinate system.

[0014] According to some embodiments, the position of the intersection can be adjusted by adjusting one or more of the following: the yaw of the wear element positioning unit; the slew angle of the telescopic crane; the luffing angle of the telescopic crane; and the telescopic extension of the crane.

[0015] According to some embodiments, the support structure comprises a mill. The interior of a mill is typically covered with wear elements in the form of liner elements. The environment within these mills is highly corrosive and dangerous, and it is desirable to reduce the amount of time that personnel have to spend in or near such mills. Also, the downtime of such mills is very costly.

[0016] According to some embodiments, the mill can be divided into different sections. Mills are typically shaped with a central cylindrical section and two conical end sections. However, some mills have flat ends, and this embodiment is also encompassed herein.

[0017] According to some embodiments, the different sections comprise a feed head; a shell; and a discharge head. The feed head and the discharge head are typically conical, and the shell is cylindrical.

[0018] According to some embodiments, an independent common coordinate system is defined for the wear element positioning device and each of the different sections. Due to the differences in shape, it is advantageous to use independent coordinate systems.

[0019] According to some embodiments, the position of the intersection determines which common coordinate system should be applied.

[0020] According to some embodiments, an operator manually moves the wear element positioning unit and directs the virtual line towards an intended placement position on the surface of the support structure, and the alignment device is configured to continuously adjust the orientation of the wear element positioning unit based on the intended placement position. This has the advantage that the wear element is kept in an orientation that will allow it to be fastened to the support structure. This is particularly advantageous when the wear element is in a position close to the support structure, i.e. in the final stage of the positioning of the wear element.

[0021] According to some embodiments, the operator manually moves the wear element positioning unit and directs the virtual line towards an intended placement position on the surface of the support structure, and the alignment device is configured to adjust the orientation of the wear element positioning unit in response to operation of the alignment actuator. This has the advantage that the orientation of the wear element does not have to be continuously rearranged. Such rearrangement is not always necessary, for example in an early stage of wear element positioning, close to the pick-up station of the wear element.

[0022] According to some embodiments, the processing device is configured to define a second coordinate system, the origin of which is in the intersection between the virtual line and the surface of the support structure.

[0023] According to a second aspect, there is provided a method for positioning a wear element relative to a support structure using a multi-axis wear element positioning apparatus having a wear element positioning unit. The method comprises the steps of:

[0024] - arranging the multi-axis wear element positioning apparatus in a replacement position relative to the support structure;

[0025] - defining a coordinate of an intersection of a virtual line originating from the multi-axis wear element positioning apparatus with the surface of the support structure;

[0026] - aligning the wear element positioning unit with the surface of the support structure at said intersection, such that a connection surface of a wear element carried by the wear element positioning unit matches a corresponding connection surface of the support structure at said intersection (Q).

[0027] The method can be advantageous in that it aligns the wear element with the surface of the support structure at the intersection of the virtual line with the surface of the support structure, i.e. at the intended placement position, such that the orientation of the wear element is ready to be fastened as if it already is at the attachment point of the support structure.

[0028] According to some embodiments, the processing device is applied to define a common coordinate system, and to define an intersection of the virtual line with the surface of the support structure, and wherein the processing device is further applied to determine an alignment orientation in which the wear element positioning unit is aligned with the surface of the support structure at said intersection, such that a connection surface of a wear element carried by the wear element positioning unit matches a corresponding connection surface of the support structure at said intersection, the processing device being configured to control the alignment device to orient the wear element positioning unit accordingly.

[0029] According to some embodiments, the virtual line is defined by directing the wear element positioning unit towards the surface of the support structure.

[0030] According to some embodiments, the virtual line originates from an attachment point of the wear element positioning unit to the multi-axis wear element positioning apparatus.

[0031] According to some embodiments, the yaw angle, the roll angle and the pitch angle of the wear element positioning unit can be adjusted by means of the alignment device.

[0032] According to some embodiments, the wear element positioning unit is arranged on a telescopic crane.

[0033] According to some embodiments, the yaw of the wear element positioning unit can be adjusted by an operator.

[0034] According to some embodiments, the slewing angle of the telescopic crane can be adjusted by an operator.

[0035] According to some embodiments, the luffing angle of the telescopic crane can be adjusted by an operator.

[0036] According to some embodiments, the telescopic extension of the telescopic crane can be adjusted by an operator.

[0037] According to some embodiments, the common coordinate system for the multi-axis wear element positioning device and the support structure originates at the origin of the telescopic crane.

[0038] According to some embodiments, the adjustment of the position of the intersection point is made by adjusting one or more of the following: the yaw of the wear element positioning unit; the slewing angle of the telescopic crane; the luffing angle of the telescopic crane; the telescopic extension of the crane; and the telescopic extension of the beam. According to some embodiments, the support structure comprises a grinding machine.

[0039] According to some embodiments, the grinding machine can be divided into different sections.

[0040] According to some embodiments, the different sections comprise a feed head; a housing; and a discharge head.

[0041] According to some embodiments, a separate common coordinate system is defined for the wear element positioning device and each of the different sections.

[0042] According to some embodiments, the position of the intersection point determines which common coordinate system should be applied.

[0043] According to some embodiments, the wear element positioning device is automatically positioned into a liner pick-up configuration if the processing device determines that the virtual line is directed towards a liner pick-up position.

[0044] According to some embodiments, an operator directs the wear element positioning unit towards the surface of the support structure, and wherein the alignment device continuously adjusts the position of the wear element positioning unit. This has the advantage that the wear element is always arranged in a position that will allow it to be fastened to the support structure. This is particularly advantageous when the wear element is in a position close to the support structure, i.e. in the last stage of the positioning of the wear element.

[0045] According to some embodiments, the operator directs the wear element positioning unit towards the surface of the support structure, and wherein the alignment device adjusts the position of the wear element positioning unit in response to operation of the alignment actuator. This has the advantage that the wear element is not always repositioned. Such repositioning is not always necessary, for example in an early stage of wear element positioning, close to the pick-up station of the wear element.

[0046] According to some embodiments, the second coordinate system is defined with its origin in the intersection between the virtual line and the surface of the support structure.

[0047] The effects and features of the second aspect are largely analogous to those described above in connection with the first aspect. The embodiments mentioned in relation to the first aspect are largely compatible with the second aspect. It is also noted that the inventive concept is concerned with all possible combinations of features unless explicitly stated otherwise.

[0048] Further scope of applicability of the present disclosure will become apparent from the detailed description given below. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the disclosure, are given by way of illustration only, since various changes and modifications within the scope of the disclosure will become apparent to those skilled in the art from this detailed description.

[0049] It should therefore be understood that the present disclosure is not limited to the particular combinations of components described or the particular steps described as the devices and methods can vary. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. It must be noted that, as used in the specification and the appended claims, the articles "a," "an," "the" and "said” are intended to mean that there are one or more of the elements unless the context clearly dictates otherwise. Thus, for example, reference to "a unit" or "the unit" can include several devices, and the like. Additionally, the words "comprising," "containing," "including," and similar wordings do not exclude other elements or steps. BRIEF DESCRIPTION OF DRAWINGS

[0050] The present disclosure will be described in greater detail by referring to the illustrative drawings.

[0051] Figure 1 A perspective view of a system for positioning a wear element according to an embodiment of the present disclosure is shown.

[0052] Figure 2 A perspective view of a system for positioning a wear element relative to a support structure arranged in a first position according to an embodiment of the present disclosure is shown.

[0053] A perspective view of a system for positioning a wear element relative to a support structure arranged in a first position according to an embodiment of the present disclosure is shown.Figure 3 A perspective view of a system for positioning a wear element relative to a support structure arranged in a second position according to embodiments of the present disclosure is shown.

[0054] Figure 4 A perspective view of a system for positioning a wear element relative to a support structure arranged in a third position according to embodiments of the present disclosure is shown.

[0055] Figure 5 A perspective view of a system for positioning a wear element relative to a support structure arranged in a third position according to embodiments of the present disclosure is shown.

[0056] Figure 6A and Figure 6B A coordinate system for implementing embodiments of the present disclosure is shown.

[0057] Figure 7A and Figure 7B Another coordinate system for implementing embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0058] The present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which current preferred embodiments of the disclosure are shown. The disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the disclosure to those skilled in the art. It should be noted that all embodiments herein show and describe a grinder with replaceable wear liner elements. However, it will be apparent to the skilled person that other applications are equally applicable to the present invention. For example, in other types of comminution equipment using replaceable wear elements, in particular in equipment where such wear elements are to be attached to planar or non-planar surfaces arranged in different directions.

[0059] Figure 1 A schematic perspective view of a system 100 for positioning a wear element relative to a support structure (e.g. a grinder (not shown) in Figure 1 The system is sometimes referred to as a Mill Reline Machine (MRM) 100. In order to be able to navigate and reach all components within e.g. a grinder, these systems typically have a large number of degrees of freedom. Figure 1 The system in is shown as having seven degrees of freedom, which can be considered quite normal for this type of application, but embodiments with more or less degrees of freedom are conceivable. A first degree of freedom L is realized by a beam 102 that can be telescopically extended and retracted. At one end 103 of the beam 102, a crane 105 is attached. The crane 105 can be telescopically extended, see Figure 1T, and positioning with respect to a swivel angle (Θ) and a luffing angle (Φ), thereby defining 3 further degrees of freedom. At the distal end of the crane 105, a 3-axis wear element positioning unit 106, also referred to as a grab or grab head 106, is arranged, which defines the last three degrees of freedom: yaw angle a, roll angle R and pitch angle P. It has been found that previous solutions requiring an operator to control all seven degrees of freedom involve a substantial loss of time, especially during the final adjustment of the 3-axis grab head 106 for orienting the wear element in a matching way to the surface of the support structure, e.g. the inner surface of a mill.

[0060] Figure 2 A mill is shown with a system 100 for positioning wear elements relative to a support structure of the mill 200, i.e. the inner surface of the mill 200. The system is sometimes referred to as a mill reliner machine (MRM) 100, which, once in place, can be firmly mounted to the mill support 202. Thus, a common coordinate system for the MRM 100 and the mill 200 can be defined, since the relative distances between the components of the MRM 100 and the components of the mill 200 are fixed and known. In Figure 2 In the shown position, the MRM 100 is positioned outside the mill 200, but has not yet been extended into the mill 200. The MRM 100 comprises a base structure 101, which can be rolled into a position in front of the mill 200 and fixed to the mill support 202 at predefined anchor points. The MRM 100 further comprises a substantially horizontal beam 102 arranged to be telescopically extended into the mill 200. The beam 102 is attached at its proximal end 104 to the base structure 101, and a crane 105 is attached to the distal end 103 of the beam 102. The crane 105 can be telescopically extended T and positioned with respect to a swivel angle (Θ) and a luffing angle (Φ) (see also Figure 1 ). At the distal end of the crane 105, a 3-axis grab or wear element positioning unit 106 is arranged.

[0061] The grab 106 is arranged to carry a wear element 150 and is movable in 3 degrees of freedom: yaw angle a, roll angle R and pitch angle P. As will be discussed in more detail later, the yaw angle a, roll angle R and pitch angle P can be calculated to orient the wear element at a placement point (e.g. an intended placement point on the inner surface of a mill housing) ready for placement on the support structure.

[0062] Although not shown in the figures, sensors can be configured to determine the actual values of each degree of freedom. These can for example include linear displacement sensors to determine the axial position of e.g. the telescopic beam 102 and the crane 105. Furthermore, angle sensors can be applied to determine the rotational position of the different components of the MRM.

[0063] The MRM also includes a processing unit 300. The processing unit is configured to receive information from various sensors, allowing it to determine the position and orientation of the wear element 150 carried by the MRM via the grab bucket 106 and various components of the MRM 100. When the MRM is locked in a fixed and known position relative to the mill 200, the processing unit can also determine the position and orientation of the MRM's components relative to the mill 200. Specifically, and as will be discussed in detail below, the processing unit is configured to determine the orientation (relative) of the wear element positioning unit 106, such that the wear element 150 carried by the wear element positioning unit 106 is ready to be assembled onto the inner surface of the mill 200.

[0064] from Figure 2 As shown in the image, the MRM 100 is ready to be moved into the grinder 200, as... Figure 3 and Figure 4 As shown. This is accomplished by moving the base structure 101 to a position in front of the opening of the mill 200, and then extending the beam 102 telescopically into the mill 200. The beam 102 may preferably, but not necessarily, extend coaxially with the centerline of the mill. Figure 3 In this configuration, beam 102 extends into the interior of the grinder 200, and grab bucket 106 remains facing outward toward the liner carriage 107, on which one or more replacement wear elements 150 can be positioned using, for example, a forklift or overhead crane. In this position, MRM 100 is ready to pick up new, unworn wear elements 150 from the liner carriage 107. Preferably, when the processing unit 300 determines that grab bucket 106 is facing the liner carriage 107, grab bucket 106 automatically orients itself in the liner pick-up position. This means that grab bucket 106 is oriented in a manner that allows the operator to easily move it toward the liner carriage 107 and pick up wear elements 150 (such as liner elements).

[0065] Now refer to Figure 4 and Figure 5wherein the mill 200 is shown in a partly open view, embodiments of the present disclosure will be discussed. An operator, who is typically standing inside the mill 200 or possibly on the platform 108, can manually operate the MRM 100 using a remote control device known in the art. The wear element 150 has been picked up and held by the grab 106, and the crane 105 together with the grab 106 of the MRM is positioned inside the mill 200. In a next step, the operator aims and directs the head 109 of the crane 105 towards an intended placement position 203 of the wear element on an inner surface 201 of the mill 200. This aiming or aligning of the head 109 towards the intended point on the inner surface 201 of the mill can be said to follow a virtual line Qg extending from the head 109 to the placement position 203. Typically, the operator adjusts the orientation of the virtual line Qg by: the extension L of the beam 102; the extension T of the crane 105; the crane swing angle Θ; the crane luffing angle φ; and the yaw angle a. Based on: available information from known and fixed relationships between the MRM and the mill 200; the dimensions of the mill 200; and information from sensors, such as angle sensors and linear displacement sensors, provided on the MRM, the processing device 300 calculates the orientation of the virtual line Qg and the coordinates of the intersection 203 of the virtual line Qg with the mill surface 201, also referred to as the placement position. Based on these coordinates, the processing device determines the orientation in which the wear element 150 must be matched with the inner surface 201 of the mill 200 at the placement position 203. This information is used to align the wear element 150 accordingly by the grab 106. This can be achieved automatically and continuously, or in response to the operator actuating an alignment actuator, such as a button provided at the remote control device. The advantage of the former solution is that the operator can focus on steering the grab towards the intended placement position, and does not need to consider the alignment of the wear element 150 at all. The advantage of the latter solution is that this alignment of the wear element 150 is only performed when it is actually needed, i.e. when the grab is close to the placement position.

[0066] Figure 6A and Figure 6BA coordinate system that can be used to implement embodiments of the present disclosure is shown. A mill coordinate system x, y, z is defined with its origin O at the crane origin, i.e. the center point of the crane swing and luff rotations of the crane 105. The x-axis is oriented along the mill rotation axis, and the z-axis is vertical. The vector between the crane origin O and the yaw actuator axis of the MRM crane head 109 is denoted t. The pointing direction of the crane boom away from the yaw actuator is indicated by the unit vector g’, and g corresponds to the unit vector g’ after a rotation of an angle a around the yaw axis u. The distance between the yaw actuator and the inner surface of the mill 200 in the direction of the unit vector g is denoted Q, i.e. the vector corresponds to a scaled version of g such that the end of Qg lies on the inner surface of the mill 200. The vector from the crane origin to the point on the inner surface of the mill where Qg terminates is denoted w, i.e. w = t + Qg. The radius from the rotation axis (coinciding with the coordinate axis x) to the inner surface of the mill is denoted r, and the crane swing and luff angles are denoted by Θ and φ, respectively.

[0067] The vector t can be expressed in terms of the crane swing and luff angles as:

[0068] t = [A x , B y , C z ]

[0069] where

[0070] A = t cos φ cos Θ

[0071] B = t cos φ sin Θ

[0072] C = t sin φ

[0073] and

[0074]

[0075] is the distance between the crane origin O and the yaw actuator axis of the MRM crane head 109.

[0076] The pointing direction of the crane boom g’ can thus be expressed as:

[0077]

[0078] The yaw axis u can be expressed as

[0079] u = [E x , F y , G z ]

[0080] where

[0081] E = -cos(90 - φ) sin(90 - θ)

[0082] F = -cos(90 - φ) cos(90 - θ)

[0083] G = sin(90 - φ)

[0084] By operating the crane 105, the MRM crane head 109 can be positioned such that it is directed towards a desired lining placement point on the inner surface of the mill. Once the crane head 109 has been positioned accordingly, the slew angle θ, the luffing angle φ and the yaw angle a can be determined using, for example, sensors such as angle sensors, also referred to as angle encoders. Then, the unit vector g in the direction towards this desired lining placement point can be expressed as:

[0085] g = R α x g' = [R x , S y , T z ]

[0086] where R α is the rotation matrix defined as:

[0087]

[0088] H = cos a + E 2 (1 - cos a)

[0089] I = E F (1 - cos a) - G sin a

[0090] J = E G (1 - cos a) + F sin a

[0091] K = E F (1 - cos a) + G sin a

[0092] L = cos a + F 2 (1 - cos a)

[0093] M = F G (1 - cos a) - E sin a

[0094] N = E G (1 - cos a) - F sin a

[0095] O = F G (1 - cos a) + E sin a

[0096] P = cos a + G 2 (1 - cos a)

[0097] and

[0098]

[0099]

[0100]

[0101] The point where the vector w terminates on the inner surface of the mill, i.e. the intersection between the imaginary line originating from the crane head 109 in the pointing direction of the crane head 109 to the inner surface of the mill, can be determined by:

[0102] W = t + Qg = [(A + QR) x ,(B + QS) y ,(C + QT) z ]

[0103] and solving for Q:

[0104] r 2 = (B + QS) 2 + (C + QT) 2

[0105] (S 2 + T 2 )Q 2 + (2BS + 2CT)Q + (B 2 + C 2 + r 2 ) = 0

[0106] a = S 2 + T 2

[0107] b = 2BS + 2CT

[0108] c = B 2 + C 2 + r 2

[0109] where Q > 0

[0110] With Figure 7A and Figure 7B , a similar derivation can be made in relation to the liner placement point on the mill head, similar for both the feed head and the discharge head. Here, in addition to the parameters discussed above, the head angle β and the offset d from the crane origin at the tip of the cone are introduced. Also, for the head cone, r will denote the radius to the cone intersection. As will be understood, the mill head can also be constructed as a flat structure, i.e. the head angle β can be zero. Any reference to a conical head in the present disclosure thus also includes a flat mill head with a head angle of zero. The point where the vector w terminates on the conical head, i.e. the intersection between the imaginary line originating from the crane head in the pointing direction of the crane head 109 to the mill conical head, can be determined as follows using the head angle β and the offset d from the crane origin at the tip of the cone.

[0111]

[0112]

[0113]

[0114]

[0115] (gl-h)Q 2 +(gm-i)Q+(gn-j) = 0

[0116] a = gl-h

[0117] b = gm-i

[0118] c = gn-j

[0119] where Q > 0

[0120] Once the intended liner placement point on the mill inner surface has been determined according to the above (i.e. the intersection between the virtual line originating from the crane head 109 to the mill inner surface), the correct yaw angle (a), roll angle R and pitch angle P of the wear element positioning unit (sometimes referred to as the liner positioning unit (LPU)) can be determined as follows in order to place the liner properly at the intended point.

[0121] First, the angle of the inner surface of the mill shell intersection (always the shell intersection, even when facing the mill head) is calculated:

[0122]

[0123] The Euler angles are then defined as

[0124] For the shell: ω = [p, 90, 0]

[0125] For the head: ω = [βsinp, βcosp, p]

[0126] The yaw angle a, roll angle R and pitch angle P of the LPU are then calculated as follows. Refer to Figure 6A , the following key points and vectors are considered:

[0127] P1 : The crane end point, defined by the vector t = [A x ,B y ,C z ] discussed above.

[0128] V1 : The normal of the yaw plane with respect to the crane end point (P1 ), which corresponds to u as described above.

[0129] P2: mill housing intersection point, defined by the vector w

[0130] V2: normal to the mill housing intersection point (P2), which can be expressed as V2 = [-sin ω y cos ω x ,sin ω x ,-cos ω y ]

[0131] V3: unit vector from the mill intersection point (P2) towards the crane endpoint (PI), which can be expressed as V3 = w - g

[0132] V4: projection of V2 (i.e. normal to the mill housing intersection point) onto the yaw plane, which can be expressed as V4 = V2 - u (V2 · u)

[0133] The LPU angle can then be determined as:

[0134]

[0135] For the mill housing:

[0136] Roll angle = ω z - φ cos θ

[0137] Pitch angle = ω x - φ sin θ

[0138] For the mill head:

[0139] Roll angle = ω z - φ sin θ

[0140] Pitch angle = ω x - φ cos θ

[0141] Thus, with reference again to Figure 6A , the yaw angle a is the angle between the virtual line projected from the head 109 of the crane 105 of the MRM 100 and the z-axis of the wear element placement point projected about the y-axis of the crane head 109 onto the yaw plane (orthogonal to the crane head y-axis).

[0142] The roll angle R is the z-axis rotation of the wear element placement point coordinate system minus the projected rotation of the crane swing angle.

[0143] The pitch angle is the x-axis rotation of the wear element placement point coordinate system minus the projected rotation of the crane swing angle.

[0144] As described herein, the yaw angle a can be adjusted both manually and by automatic alignment. Since in some embodiments the intersection of the virtual line Qg depends on the yaw angle a, which is also one of the parameters adjusted by the alignment device, the system will work in a closed loop, i.e. the intersection will be recalculated after each incremental adjustment of the alignment device.

[0145] It is clear that the invention as disclosed herein provides a substantial improvement over prior art solutions. The task of the operator is simplified, since the fine alignment of the wear element, which is performed in order to achieve a match of the surface of the wear element and the inner surface of the mill, is now done in a semi- or fully automatic manner, thereby reducing the downtime of the mill. The operator only needs to move the grab towards the intended drop point, and the device adjusts the orientation of the grab, and thus of the wear element, in response to this movement.

[0146] The person skilled in the art realizes that the present disclosure is by no means limited to the preferred embodiments described above. On the contrary, many modifications and changes are possible in light of the above teaching.

[0147] For example, although embodiments are shown in relation to a grinding mill, the present disclosure is by no means limited to such a device. The person skilled in the art realizes that the invention as defined herein can also be applied to other devices, wherein a wear element, such as a liner, needs to be handled by a machine having multiple degrees of freedom, similar to the MRM described herein. For example, in other types of crushing devices. Furthermore, although it has been described that the virtual line originates from the crane head and that the operator directs the crane towards the intended drop point of the support structure, other variants are conceivable within the scope of the present disclosure. For example, the virtual line can originate from any point, as long as its orientation relative to the MRM and the support structure can be determined. For example, the virtual line can be defined by a laser pointer mounted to the MRM or any part of the mill, such as the location where the operator is located. The laser pointer can be provided with an angle encoder, so that the intersection of the laser with the inner surface of the mill can be determined. Furthermore, the order in which the different degrees of freedom are adjusted can be different. For example, in the figures, the pitch (angle) is indicated as being downstream of the roll (angle). Of course, the pitch (angle) can alternatively be arranged upstream of the roll (angle), within the scope of the invention.

[0148] In addition, variations to the disclosed embodiments can be understood and effected by the skilled person in the art from a study of the drawings, the disclosure, and the appended claims.

Claims

1. Method of positioning a wear element relative to a support structure using a multi-axle wear element positioning apparatus having a wear element positioning unit, the method comprising the steps of: arranging the wear element positioning apparatus in a replacement position relative to the support structure; defining coordinates of an intersection (203) of a virtual line (Qg) with a surface of the support structure, wherein the virtual line (Qg) is defined by a pointing direction of the multi-axle wear element positioning apparatus; aligning the wear element positioning unit with the surface of the support structure at the intersection (203) such that a connection surface of the wear element carried by the wear element positioning unit at the intersection (203) matches a corresponding connection surface of the support structure, wherein a processing device is applied to define a common coordinate system for the multi-axle wear element positioning apparatus and the support structure and to define the intersection (203) of the virtual line (Qg) with the surface of the support structure in the common coordinate system, and wherein the processing device is further applied to determine an alignment of the wear element positioning unit with the surface of the support structure at the intersection (203) such that the connection surface of the wear element carried by the wear element positioning unit at the intersection (203) matches the corresponding connection surface of the support structure, the processing device being configured to control an alignment device to orient the wear element positioning unit accordingly.

2. The method of claim 1, wherein, if the processing device determines that the virtual line (Qg) is directed towards a liner pick-up position, the wear element positioning apparatus is automatically positioned instead into a liner pick-up configuration.

3. The method of claim 2, wherein, the liner pick-up position comprises a liner car carrying a replacement liner element.

4. The method of any one of claims 1 to 3, wherein, an operator manually directs the wear element positioning unit along the virtual line (Qg) towards the surface of the support structure, and wherein the alignment device continuously adjusts the orientation of the wear element positioning unit.

5. The method of any one of claims 1 to 3, wherein, an operator manually directs the wear element positioning unit along the virtual line (Qg) towards the surface of the support structure, and wherein the alignment device adjusts the position of the wear element positioning unit in response to operation of an alignment actuator.

6. The method of any one of claims 1 to 3, wherein, the virtual line (Qg) originates from the multi-axle wear element positioning apparatus.

7. The method of any one of claims 1 to 3, wherein, the virtual line (Qg) is defined by directing the wear element positioning unit towards the surface of the support structure.

8. The method of any one of claims 1 to 3, wherein, the virtual line (Qg) originates from a point of attachment of the wear element positioning unit to the multi-axle wear element positioning apparatus.

9. The method of any one of claims 1 to 3, wherein, one or more of a yaw angle (a), a roll angle (R) of the wear element positioning unit, and a pitch angle (P) of the wear element positioning unit can be adjusted by the alignment device.

10. The method of any one of claims 1 to 3, wherein, the wear element positioning unit is arranged on a telescoping crane.

11. The method of any one of claims 1 to 3, wherein, a yaw angle of the wear element positioning unit can be adjusted by an operator.

12. The method of claim 10, wherein, a slewing angle (0) of the telescoping crane can be adjusted by an operator.

13. The method of claim 10, wherein, a luffing angle (f) of the telescoping crane can be adjusted by an operator.

14. The method of claim 9, wherein, a telescoping extension of the telescoping crane can be adjusted by an operator.

15. The method of claim 9, wherein, The common coordinate system originates at an origin of a telescopic crane.

16. The method according to any one of claims 1 to 3, comprising adjusting the position of the intersection point (203) by adjusting one or more of: a yaw angle of the wear element positioning unit, a slew angle of a telescopic crane, a luffing angle of a telescopic crane, a telescopic extension of a crane, and a telescopic extension of a beam.

17. The method of any one of claims 1 to 3, wherein, The support structure comprises a grinding machine.

18. The method of claim 17, wherein, The grinding machine can be divided into different segments.

19. The method of claim 18, wherein, The different segments comprise a feed head, a housing, and a discharge head.

20. The method of claim 18, wherein, A separate common coordinate system is defined for the wear element positioning device and each of the different segments.

21. The method of claim 20, wherein, The position of the intersection point (203) determines which common coordinate system should be applied.

22. System for positioning a wear element relative to a support structure, the system comprising: a multi-axis wear element positioning device having a wear element positioning unit, wherein the wear element positioning device can be arranged in a replacement position relative to the support structure; a processing arrangement arranged to determine coordinates of an intersection point (203) of a virtual line (Qg) intersecting a surface of the support structure, wherein the virtual line (Qg) is defined by a pointing direction of the multi-axis wear element positioning device; wherein the processing arrangement is further arranged to automatically determine an orientation of the wear element positioning unit in which a wear element carried by the wear element positioning unit is aligned with the surface of the support structure at the intersection point (203) such that a connection surface of the wear element matches a corresponding connection surface of the support structure at the intersection point (203), the processing arrangement being configured to control an alignment device to orient the wear element positioning unit accordingly; wherein the processing arrangement is applied to define a common coordinate system for the multi-axis wear element positioning device and the support structure, and to define the intersection point (203) of the virtual line (Qg) intersecting the surface of the support structure in the common coordinate system.

23. The system of claim 22, wherein, The virtual line (Qg) originates from the multi-axis wear element positioning device.

24. The system of claim 23, wherein, The virtual line (Qg) is defined such that the wear element positioning unit is arranged to be directed towards the surface of the support structure.

25. The system of claim 22, wherein, The virtual line (Qg) originates from a point of attachment of the wear element positioning unit to the multi-axis wear element positioning device.

26. The system of any one of claims 22-25, wherein, One or more of a yaw angle (a) of the wear element positioning unit, a roll angle (R) of the wear element positioning unit, and a pitch angle (P) of the wear element positioning unit can be adjusted by the alignment device.

27. The system of any one of claims 22-25, wherein, The wear element positioning unit is arranged on a telescopic crane.

28. The system of any one of claims 22-25, wherein, The yaw angle (a) of the wear element positioning unit can be adjusted by an operator.

29. The system of claim 27, wherein, The slew angle (Q) of the telescopic crane can be adjusted by an operator.

30. The system of claim 27, wherein, The luffing angle (f) of the telescopic crane can be adjusted by an operator.

31. The system of claim 27, wherein, The telescopic extension of the telescopic crane can be adjusted by an operator.

32. The system of claim 27, wherein, A common coordinate system for the multi-axis wear element positioning apparatus and the support structure originates at the origin of the telescoping crane.

33. The system of claim 27, wherein, The position of the intersection (203) can be adjusted by adjusting one or more of: a yaw angle of the wear element positioning unit, a slew angle of the telescoping crane, a luffing angle of the telescoping crane, a telescoping extension of the crane, and a telescoping extension of the beam.

34. The system of any one of claims 22 to 25, wherein, The support structure comprises a grinder.

35. The system of claim 34, wherein, The grinder can be divided into different sections.

36. The system of claim 35, wherein, The different sections comprise a feed head, a housing, and a discharge head.

37. The system of claim 35, wherein, A separate common coordinate system is defined for the wear element positioning apparatus and each of the different sections.

38. The system of claim 37, wherein, The position of the intersection (203) determines which common coordinate system should be applied.

39. The system of any one of claims 22-25, wherein, An operator manually guides the wear element positioning unit along a virtual line (Qg) towards a surface of the support structure, and wherein the alignment device is configured to continuously adjust the position of the wear element positioning unit.

40. The system of any one of claims 22-25, wherein, An operator manually guides the wear element positioning unit along a virtual line (Qg) towards a surface of the support structure, and wherein the alignment device is configured to adjust the position of the wear element positioning unit in response to operation of an alignment actuator.

41. The system of any one of claims 22-25, wherein, The processing device is arranged to determine whether the virtual line (Qg) is directed towards a liner pick-up position.

42. The system of claim 41, wherein, If the virtual line is directed towards the liner pick-up position, the wear element positioning apparatus is automatically positioned instead into a liner pick-up configuration.

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