Self-propelled milling machine with machine frame and material removal conveyor

Abstract

The invention relates to a self-propelled milling machine, in particular a road milling machine or a surface miner, having a machine frame supported by a running gear, a working device arranged on the machine frame for working on the ground, and a conveyor device for removing material. The conveyor device has a boom which is mounted on the machine frame so as to be pivotable about a rotation axis perpendicular to the machine frame. The pivot device for the boom is characterized by at least one mechanism having a plurality of mechanism links and joints connecting them and at least one linear drive for driving at least one of the mechanism links. The mechanism is preferably designed as a planar four-bar linkage pivot joint mechanism, the machine frame forming a mechanism link of the pivot joint mechanism. A particularly preferred embodiment provides that the pivot device has a first and a second four-bar linkage pivot joint mechanism which are arranged mirror-symmetrically with respect to a longitudinal center plane of the machine frame.

Description

Technical Field

[0001] This invention relates to a self-propelled milling machine, particularly a road milling machine or open-pit mining machine, which has an adjustable-height machine frame supported by a traveling mechanism, a working device for working on the ground mounted on the machine frame, and a conveying device for removing materials. Background Technology

[0002] Known self-propelled milling machines typically have a machine frame supported by a chassis with multiple tracked traveling devices. Self-propelled milling machines are known to have working devices for operating on the ground, such as those for removing damaged road layers (road milling machines) or for mining mineral resources (open-pit mining machines). The working devices of road milling machines and open-pit mining machines have milling drums arranged on the machine frame. The individual traveling mechanism units of road milling machines and open-pit mining machines are configured with lifting devices including piston / cylinder arrangements to enable the machine frame, along with the milling drums, to be lowered, raised, or tilted relative to the ground (soil surface).

[0003] To transport milled or mined material, road milling machines and open-pit mining machines have conveyor systems with cantilevered arms that pivot laterally and a circular conveyor belt, so that loose material (bulk material) can fall onto the loading surface of a mobile transport vehicle (truck) moving with the milling machine during operation. The cantilever of a road milling machine typically has a support mounted on the machine frame for pivoting about an axis of rotation substantially perpendicular to the machine frame. A pivoting device driven by a drive unit is provided for pivoting the cantilever. Typically, an operating unit is provided on which the position of the cantilever can be adjusted by the machine operator. However, auxiliary systems that relieve the machine operator of this task are also known.

[0004] The machine operator should be able to easily and precisely adjust the angle of the boom, and the boom should have a sufficient range of pivoting to safely dump material onto the truck's loading surface.

[0005] WO 01 / 31301 A1 describes a road milling machine with a conveying device having a pivotable cantilever. The pivoting device includes a piston / cylinder arrangement where the piston is hinged to a support of the cantilever, and the cylinder is hinged to the machine frame. The support pivots by moving the piston in and out. WO 2014 / 029824 A1 discloses a road milling machine with a pivoting device for the cantilever having two piston / cylinder arrangements, one arranged on one side of the longitudinal center plane of the machine frame, and the other arranged on the other side of the longitudinal center plane of the machine frame.

[0006] The aforementioned pivoting device for road milling machines has a simple structure. However, a drawback is that the torque applied by the piston / cylinder arrangement, which exerts a constant force, is not approximately constant throughout the pivoting range. The torque is greatest in the minimum deflection range and least in the maximum deflection range. Due to the high torque, the piston / cylinder arrangement must be large enough, resulting in higher cost, greater weight, and greater space requirements.

[0007] US Patent 5,178,253 A1 describes a pivoting device for a milling machine having a first piston / cylinder arrangement on one side of the longitudinal center plane of the machine frame and a second piston / cylinder arrangement on the other side of the longitudinal center plane of the machine frame, the cylinders of the first and second piston / cylinder arrangements being hinged to the machine frame. The piston of each piston / cylinder arrangement is hinged to one end of a mechanism link, the other end of which is hinged to a cantilever. When the piston of the first piston / cylinder arrangement retracts, the cantilever pivots to one side, and when the piston of the second piston / cylinder arrangement retracts, the cantilever pivots to the other side. When the piston of one piston / cylinder arrangement retracts, the piston of the other piston / cylinder arrangement is pulled out of its cylinder. Therefore, only one of the two piston / cylinder arrangements applies a pulling force. Since one piston / cylinder arrangement is not supported by the other, the piston / cylinder arrangement and the associated hydraulic system must be sized sufficiently to apply the required force. Summary of the Invention

[0008] The object of this invention is to improve the pivoting device of the conveyor system in a self-propelled milling machine. A particular object of this invention is to simplify the operation of the pivoting device, thereby allowing the machine operator to easily and accurately set the position of the cantilever.

[0009] According to the present invention, this objective is achieved by the features described below.

[0010] The self-propelled milling machine according to the invention, particularly a road milling machine or an open-pit mining machine, has a machine frame supported by a traveling mechanism, a working device disposed on the machine frame for working on the ground, and a conveying device for removing material (bulk material), the conveying device having a cantilever mounted on the machine frame for pivoting about a rotation axis substantially perpendicular to the machine frame.

[0011] In this context, a pivotable cantilever is understood as any protruding component that can pivot at a specific pivot angle in a plane extending transversely to the longitudinal center plane of the machine frame (i.e., in a horizontal plane when the machine frame is horizontally aligned). However, a cantilever can also pivot at a specific tilt angle in a vertical plane perpendicular to it.

[0012] The pivoting device of the milling machine according to the invention includes at least one mechanism and at least one linear drive, the mechanism having a plurality of mechanism links and joints connecting them, the linear drive being used to drive at least one mechanism link.

[0013] The mechanism of the pivoting device allows for user-friendly operation by the machine operator. The pivoting device is characterized by the cantilever's ability to pivot at approximately the same speed throughout its entire pivot range. Therefore, the machine operator can easily and precisely adjust the cantilever. This mechanism prevents the movement of the linear drive at specific angles (e.g., maximum or minimum deflection) from resulting in excessively rapid pivoting motion. Furthermore, using the pivoting device according to the invention, a substantially constant torque can always be applied to the cantilever throughout its entire pivot range.

[0014] Linear actuators are understood to be all drive mechanisms that cause translational motion. These drive mechanisms include, for example, piston / cylinder arrangements or screw mechanisms.

[0015] In a preferred embodiment, the pivoting device is designed as a planar four-bar pivot joint mechanism, with the machine frame forming the linkages of the pivot joint mechanism. A particularly preferred embodiment specifies that the pivoting device has a first four-bar pivot joint mechanism and a second four-bar pivot joint mechanism, arranged mirror-symmetrically with respect to the longitudinal center plane of the machine frame. In embodiments with two pivot joint mechanisms, the two mechanisms may share at least one common linkage and / or joint.

[0016] A particular advantage of the pivoting device according to the invention is that the linear actuator for one of the drive mechanism links can operate in both directions. Therefore, it is possible that the pivoting device may comprise only one four-bar pivot joint mechanism through which the boom can pivot in both directions. However, if the milling machine has two four-bar pivot joint mechanisms, the size of the two drive units can be smaller because they support each other, thus saving space and cost.

[0017] The four-bar pivot joint mechanism allows the cantilever to pivot at a relatively constant speed throughout its entire pivot range. Therefore, in practice, the machine operator can accurately and safely pivot the cantilever to the desired position, thus improving the operability (maneuverability) of the milling machine. Furthermore, the four-bar pivot joint mechanism allows for a relatively uniform torque curve throughout the entire pivot range. Finally, the four-bar pivot joint mechanism increases the pivot range.

[0018] In one embodiment, the first four-bar pivot joint mechanism and / or the second four-bar pivot joint mechanism include a first mechanism link, one end of which is hinged to the machine frame via a first joint, the other end of which is hinged to one end of a second mechanism link via a second joint, the other end of which is hinged to one end of a third mechanism link via a third joint, and the other end of which is hinged to the machine frame via a fourth joint.

[0019] The linkages and joints can have various designs. For example, the linkage can be formed from a bar, plate, belt, or part of a machine frame and / or cantilever. The joint can have pins and bushings. The first linkage of a first four-bar pivot joint mechanism and / or a second four-bar pivot joint mechanism can be formed from a single bar, and the second linkage of the first four-bar pivot joint mechanism and / or the second four-bar pivot joint mechanism can be formed from two spaced-apart bars, with one end of the first linkage bar rotatably mounted between the ends of the two bars of the second linkage. However, the first linkage may also be formed from two bars spaced apart from each other, and the second linkage may also be formed from a single bar, with one end of the second linkage bar rotatably mounted between the ends of the two bars of the first linkage.

[0020] The linear actuator may have a first piston / cylinder arrangement, wherein the piston of the first piston / cylinder arrangement is hinged at one end to the machine frame, and the cylinder of the first piston / cylinder arrangement is hinged at one end to one of the links of a first four-bar pivot joint mechanism, and / or may have a second piston / cylinder arrangement, wherein the piston of the second piston / cylinder arrangement is hinged at one end to the machine frame, and the cylinder of the second piston / cylinder arrangement is hinged at one end to one of the links of a second four-bar pivot joint mechanism. Alternatively, the linear actuator may have a first piston / cylinder arrangement, wherein the cylinder of the first piston / cylinder arrangement is hinged at one end to the machine frame, and the piston of the first piston / cylinder arrangement is hinged at one end to one of the links of a first four-bar pivot joint mechanism, and may also have a second piston / cylinder arrangement, wherein the cylinder of the second piston / cylinder arrangement is hinged at one end to the machine frame, and the piston of the second piston / cylinder arrangement is hinged at one end to one of the links of a second four-bar pivot joint mechanism.

[0021] The piston or cylinder of either the first or second piston / cylinder arrangement can be hinged at one end to a second linkage of either the first or second four-bar linkage. This connection allows for optimal transmission of tensile or compressive forces with a relatively short overall length for the respective piston / cylinder arrangement. However, the piston or cylinder can also be hinged to either the first or third linkage.

[0022] The second linkage may have a flange on which the piston or cylinder of the first piston / cylinder arrangement or the second piston / cylinder arrangement is hinged at one end to the second linkage of the first four-bar linkage or the second four-bar linkage. However, the hinged connection from the piston / cylinder arrangement to the linkage may also be made directly at the joint of one of the linkages.

[0023] A cantilever may include a support frame and a frame, the support frame being fastened to the machine frame for rotation about a central horizontal axis, and the frame being mounted in the support frame for pivoting about a vertical axis. For example, the frame of the cantilever may accommodate a belt conveyor. This type of cantilever is prior art.

[0024] One embodiment specifies that the third mechanism link of the first four-bar pivot joint mechanism and the second four-bar pivot joint mechanism is formed by a bracket mounted on a cantilever, the bracket being mounted on the machine frame to pivot about a rotation axis located in the longitudinal center plane of the machine frame.

[0025] A substantially constant pivoting speed and a uniform torque curve can be achieved at a sufficiently large pivoting angle in the following situations: when the pivoting angle is zero, i.e., when the cantilever is not pivoting, the angle α enclosed by the first piston / cylinder arrangement and the second piston / cylinder arrangement is between 40° and 80°, preferably between 50° and 70°, and / or when the cantilever is not pivoting, the angle α enclosed by the first mechanism link of the first four-bar pivot joint mechanism and the second four-bar pivot joint mechanism is between 30° and 50°, preferably between 20° and 40°, and / or when the cantilever is not pivoting, the angle α enclosed by the second mechanism link of the first four-bar pivot joint mechanism and the second four-bar pivot joint mechanism is between 70° and 110°, preferably between 80° and 100°.

[0026] The first joints of the first and second four-bar pivot joint mechanisms are preferably located in the transverse plane of the machine frame, which is perpendicular to the longitudinal center plane. Depending on the available space, the first joints of the two pivot joint mechanisms may also be offset from each other in the longitudinal direction of the machine frame. However, they may also form a common joint. The third joints of the first and second four-bar pivot joint mechanisms preferably form a common joint. However, they may also be joints offset from each other.

[0027] In a further embodiment, the milling machine has a hydraulic unit for actuating a first piston / cylinder arrangement and a second piston / cylinder arrangement. This hydraulic unit is designed such that, in a first operating mode, the piston of the first piston / cylinder arrangement extends and the piston of the second piston / cylinder arrangement retracts, causing the cantilever to pivot to one side; and in a second operating mode, the piston of the first piston / cylinder arrangement retracts and the piston of the second piston / cylinder arrangement extends, causing the cantilever to pivot to the other side. Because the piston / cylinder arrangement is a double-acting arrangement, the forces acting on the first and second piston / cylinder arrangements are smaller than if only one of the two piston / cylinder arrangements were active in one direction during the pivoting motion. Therefore, the size of the piston / cylinder arrangements and the associated hydraulic unit can be correspondingly smaller.

[0028] An operating unit can be provided for the machine operator, which interacts with the hydraulic unit and has at least one operating element (e.g., lever, switch, button, etc.). The operating unit can be designed such that at least one operating element takes a first position for pivoting the cantilever in one direction and a second position for pivoting the cantilever in another direction, thereby allowing the hydraulic unit to fill hydraulic fluid into the corresponding cylinder chamber of the relevant piston / cylinder arrangement. Attached Figure Description

[0029] Embodiments of the present invention will now be explained in more detail with reference to the accompanying drawings, wherein:

[0030] Figure 1 It is a side view of a self-propelled milling machine with a conveyor and a transport vehicle;

[0031] Figure 2 This is a perspective view of an embodiment of the pivoting device of a self-propelled milling machine according to the present invention;

[0032] Figure 3 It comes from Figure 2 A plan view of the pivoting device in the middle;

[0033] Figure 4 yes Figure 2 A schematic diagram of a planar four-bar pivot joint mechanism for a pivoting device;

[0034] Figure 5A A pivoting device according to the invention is shown, wherein the cantilever support is not pivoted;

[0035] Figure 5B A pivoting device is shown, wherein the cantilevered support pivots through a first angle;

[0036] Figure 5C A pivoting device is shown, wherein the cantilever support pivots through a second angle greater than a first angle;

[0037] Figure 5D A pivoting device is shown, wherein the cantilever support pivots through a third angle greater than the second angle;

[0038] Figure 5E A pivoting device is shown, wherein the cantilever support pivots through a fourth angle greater than the third angle;

[0039] Figure 6 A hydraulic circuit diagram for a hydraulic unit used in an actuating piston / cylinder arrangement is shown; and

[0040] Figure 7 It shows a graph of pivot speed and torque based on pivot angle. Detailed Implementation

[0041] Figure 1 This is a side view of the self-propelled milling machine 1 together with the transport vehicle 2. The milling machine 1 has a machine frame 4 supported by a chassis 3, on which a working device 5 is arranged, through which the work required for the construction project can be performed.

[0042] In the working direction I, the milling machine 1 has a left front traveling mechanism 6A and a right front traveling mechanism, as well as a left rear traveling mechanism 6B and a right rear traveling mechanism. The left front lifting device 7A and the right front lifting device, as well as the left rear lifting device 7B and the right rear lifting device, are assigned to the traveling mechanism in the working direction I, so that the height and inclination of the machine frame 4 relative to the ground G can be changed by retracting or extending the lifting device.

[0043] The milling machine 1 is a road milling machine (large milling machine) used for milling road surfaces. In this road milling machine, the working device 5 has a milling drum 8, which is arranged in a milling drum housing 9 (indicated only in outline) located between the front and rear traveling mechanisms. Above the milling drum housing 9, a machine operator's workbench 10 is located on the machine frame, and the workbench has an operating unit 11 for the machine operator. The operating unit has operating elements 11A.

[0044] To remove the milled material, the road milling machine has a conveyor 12, which includes a cantilever 13 with a frame 14 on which a circular conveyor belt 35 (indicated by dashed lines) is arranged. The cantilever 13 has a support 15 mounted on the front side of the machine frame 4 to pivot about a rotation axis X substantially perpendicular to the machine frame, so that the cantilever 13 can pivot in the horizontal plane.

[0045] Since the road milling machine or open-pit mining machine is a front-loading milling machine, a transport vehicle 2 carrying the milling material as bulk material travels in front of the milling machine. However, the road milling machine or open-pit mining machine can also be a rear-loading milling machine, in which the support 15 of the cantilever 13 is mounted at the rear of the milling machine so as to pivot about a rotation axis that is substantially perpendicular to the machine frame.

[0046] The terms “vertical” and “horizontal” used below refer to the flat contact surface of the milling machine and assume that the machine frame is not tilted relative to the ground in the longitudinal and / or transverse directions.

[0047] The machine operator can adjust the horizontal pivot position of the cantilever 13 by actuating the operating element 11A of the operating unit 11. If the transport vehicle 2 is laterally deviated from the milling machine 1, the machine operator can pivot the cantilever 13 to one side or the other side by an appropriate angle so that the milled material can fall onto the loading surface of the transport vehicle.

[0048] Provide pivoting device 16 ( Figure 1 (Not shown in the image) is used to pivot the cantilever 13 in the horizontal plane, with reference to... Figures 2 to 7 The pivoting device is described in detail. The cantilever 13 can also pivot in the horizontal plane. For this purpose, the frame 14 of the cantilever 13 is mounted on a bracket 15 for pivoting about a horizontal axis Y. The height of the cantilever 13 is adjusted via a piston-cylinder arrangement 37, whose piston 37A is hinged to the frame 14 of the cantilever 13 and whose cylinder 37B is hinged to the bracket 15. However, this pivoting device is not the subject of this invention.

[0049] The drive power for the travel drive and working device, as well as other units of the milling machine, is provided by an internal combustion engine. Figure 1 (Not shown in the image).

[0050] Figure 2 A perspective view shows a portion of the machine frame 4 of the milling machine according to the invention, a portion of the support 15 of the cantilever 13, and the pivoting device 16 according to the invention. How the corresponding portions of the support and the machine frame are designed is irrelevant to the invention. In this respect, Figure 2 The specific designs of these parts shown are for illustrative purposes only. It is irrelevant whether the bracket is fastened to the front or rear of the milling machine (front loader or rear loader).

[0051] Figure 3The pivoting device 16, support 15, and therefore cantilever 13 are shown in a plan view in their initial position (pivot angle α = 0°). For a front-loading milling machine, "left" and "right" as used below refer to the milling machine's operating direction I. The central vertical axis of rotation X of the support 15 lies in the longitudinal center plane of the machine frame 4, and the longitudinal axis Z of the machine frame lies in this plane. The pivoting device 16 has a structure that is mirror-symmetrical with respect to the longitudinal center plane, and includes... Figure 3 The first planar four-bar pivot joint mechanism 16A on the left side and Figure 3 The mechanism comprises a second planar four-bar pivot joint 16B on the right side, a left linear actuator 17A for driving the first planar four-bar pivot joint 16A on the left side, and a right linear actuator 17B for driving the second planar four-bar pivot joint 16B on the right side. The left linear actuator 17A and the right linear actuator 17B may have piston / cylinder arrangements 18, 18'. It should be noted that the two linear actuators operate together and drive both mechanisms together. Even with only one linear actuator, both mechanisms will be driven.

[0052] Figure 4 The diagram shows the connecting rods and joints of the two pivot joint mechanisms. Figure 3 and Figure 4 The corresponding connecting rods and joints are labeled with the same reference numerals.

[0053] The first planar four-bar pivot joint mechanism 16A on the left side includes a first mechanism link 101, one end of which is hinged to the machine frame 4 via a first joint A, and the other end of which is hinged to one end of a second mechanism link 102 via a second joint B. The other end of the second mechanism link 102 is hinged to one end of a third mechanism link 103 via a third joint C, and the other end of the third mechanism link 103 is hinged to the machine frame 4 via a fourth joint D. A fourth mechanism link 104 is formed by a portion 4A of the machine frame 4 protruding from the front or rear of the milling machine. Therefore, the fourth mechanism link 104 is defined as a frame. The first mechanism link 101 is a flat bar (flat profile), and the second mechanism link 102 is formed by two flat bars (flat profiles). The first mechanism link 101 is rotatably mounted between the two flat bars (flat profiles).

[0054] The rotation center axis X of the support 15 of the cantilever 13 is located at the center of the protrusion 4A of the machine frame 4 in the longitudinal center plane, and the rotation axis of the first joint A is located on the upper left side of the longitudinal center plane. When the support 15 is in the initial position, the rotation axis of the third joint C is located in the longitudinal center plane.

[0055] The second mechanism link 102 has a flange 102A that extends laterally outward beyond the second joint B to the left. The free end of the first piston 18A of the left piston / cylinder arrangement 18 is hinged at joint E to the outer flange 102A of the second mechanism link 102, while the cylinder 18B of the left piston / cylinder arrangement 18 is hinged at joint F to the bearing seat 4B of the machine frame 4 (frame). Figure 3 It is shown only schematically.

[0056] The second planar four-bar pivot joint mechanism 16B on the right has the same structure as the first planar four-bar pivot joint mechanism 16A on the left. The mechanism links and joints of the right pivot joint mechanism are therefore indicated by apostrophe reference numerals.

[0057] The third joints C, C' and the fourth joints D, D' of the first-plane four-bar pivot joint mechanism 16A on the left and the second-plane four-bar pivot joint mechanism 16B on the right are each composed of common rotating joints C, C' and D, D'. The first joints A, A' of the first-plane four-bar pivot joint mechanism 16A on the left and the second-plane four-bar pivot joint mechanism 16B on the right are located on each side of the longitudinal center plane in a transverse plane that is transverse to the longitudinal center plane.

[0058] In this embodiment, when the cantilever 13 is not pivoting, the left piston / cylinder arrangement structure 18 of the left first planar four-bar pivot joint mechanism 16A and the right piston / cylinder arrangement structure 18' of the right second planar four-bar pivot joint mechanism 16B form an angle of 54°. When the cantilever 13 is not pivoting, the first mechanism links 101 and 101' of the left first planar four-bar pivot joint mechanism 16A and the right second planar four-bar pivot joint mechanism 16B form an angle of 24°. When the cantilever 13 is not pivoting, the second mechanism links 102 and 102' of the left first planar four-bar pivot joint mechanism 16A and the right second planar four-bar pivot joint mechanism 16B form an angle of approximately 90°.

[0059] The degrees of freedom (F) of a planar mechanism depend on the number of links (including the frame) n and the number of joints g with corresponding joint degrees of freedom (f). A pivot joint has a joint degree of freedom f = 1.

[0060] Grübler's operating conditions apply to both the first-plane four-bar pivot mechanism 16A and the second-plane four-bar pivot mechanism 16B:

[0061] F = 3(n-1) - 2g, where n = 4 and g = 4

[0062] F=1

[0063] With F=1 degree of freedom, the first planar four-bar pivot joint mechanism 16A and the second planar four-bar pivot joint mechanism 16B cause forced operation. When the first piston 18A of the left piston / cylinder arrangement 18 extends, the bracket 15 pivots clockwise to the right; when the first piston 18A of the left piston / cylinder arrangement 18 retracts, the bracket pivots counterclockwise to the left. When the second piston 18A' of the right piston / cylinder arrangement 18' extends, the bracket 15 pivots counterclockwise to the left; when the second piston 18A' of the right piston / cylinder arrangement 18' retracts, the bracket pivots clockwise to the right. When the cantilever 13 pivots, the axis of the joint moves along the predetermined path 19. Figure 4 When the piston of one piston / cylinder arrangement extends, the piston of the other piston / cylinder arrangement is pressed into the cylinder, and vice versa. Therefore, the cantilever 13 can be pivoted using only one pivot joint mechanism. However, a dual pivot joint mechanism including a first planar four-bar pivot joint mechanism 16A and a second planar four-bar pivot joint mechanism 16B has the advantage that the piston / cylinder arrangements 18 and 18' can be actuated simultaneously, thus requiring a smaller force for pivoting. Consequently, the size of the piston / cylinder arrangement can be reduced, saving cost, weight, and space.

[0064] Figures 5A to 5E The movement of the cantilever 13 or its support 15 is shown when the piston / cylinder arrangement 18, 18' is actuated. It is demonstrated that the pivoting device 16 allows a relatively large pivot angle of 90°.

[0065] In order to actuate the piston / cylinder arrangement 18, 18', the milling machine has a hydraulic unit 20, which may be part of the milling machine's hydraulic system (not shown). Figure 6 The hydraulic circuit diagram of hydraulic unit 20 is shown. The piston / cylinder arrangement structures 18 and 18' are double-acting piston / cylinder arrangement structures, each having a first chamber and a second chamber.

[0066] The hydraulic unit 20 includes a hydraulic pump 21, which in this embodiment is a variable displacement pump with an electromagnetically controlled proportional pressure control valve controlled by a central control unit (not shown) to control the pump's volumetric flow rate. A suction line 22 leading to the oil tank 23 is connected to the suction connection 21A of the hydraulic pump 21, allowing the pump to draw in hydraulic fluid from the oil tank. A first hydraulic line 24 branches into a first branch 24A and a second branch 24B. The first hydraulic line 24 is connected to the pressure connection 21B of the hydraulic pump 21. The first branch 24A is connected to the connection of the first chamber 18C of the first (left) piston / cylinder arrangement 18, and the second branch 24B is connected to the connection of the second chamber 18D' of the second (right) piston / cylinder arrangement 18'. From the connection point of the second chamber 18D of the first piston / cylinder arrangement 18 and the connection point of the first chamber 18C' of the second piston / cylinder arrangement 18', the branch lines 25A and 25B of the second hydraulic line 25 lead to the oil tank 23. A 4 / 3-way proportional valve 26 is provided in the first hydraulic line 24 and the second hydraulic line 25. This proportional valve allows flow in the line to be interrupted, established, or reversed based on the valve's position. Load holding valves 27A, 27B, or 27A' and 27B' are provided in the first branch line 24A of the first hydraulic line 24, the second branch line 24B of the second hydraulic line 24, or the branch lines 25A and 25B of the second hydraulic line 25 to prevent uncontrolled movement of the cantilever 13.

[0067] In one position, when the proportional valve 26 is actuated, hydraulic fluid flows into the first chamber 18C of the first piston / cylinder arrangement 18 and the second chamber 18D' of the second piston / cylinder arrangement 18', causing the first piston 18A to extend and the second piston 18A' to retract, thereby pivoting the cantilever 13 to the right. In another position, hydraulic fluid flows into the second chamber 18D of the first piston / cylinder arrangement 18 and the first chamber 18C' of the second piston / cylinder arrangement 18', causing the first piston 18A to retract and the second piston 18A' to extend, thereby pivoting the cantilever 13 to the left.

[0068] In this embodiment, the operating unit 11, which interacts with the control unit or hydraulic unit, has a control lever that can pivot left or right from a neutral position. When the machine operator pivots the control lever to the left or right, the 4 / 3-way proportional valve 26 is actuated, causing the cantilever 13 to pivot left or right.

[0069] The pivoting device 16 according to the invention is characterized in that the angular velocity of the cantilever 13 rotating in one direction or the other is substantially constant throughout the entire pivoting range. It should be noted that this is achieved by a constant volumetric flow rate of the hydraulic fluid supplied by the hydraulic pump 21, or a constant actuation of the proportional valve, or a constant deflection of the control lever. The sensitivity of the cantilever control stems, on the one hand, from the fact that the directional valve is a proportional directional valve, meaning the machine operator can freely select the pivoting speed of the cantilever, and on the other hand, from the fact that the mechanism is designed to maintain a constant pivoting speed even when the drive speed of at least one linear actuator is constant, thus preventing the machine operator from being disturbed by speed fluctuations when operating the control lever. Therefore, the pivoting device allows the machine operator to perform fine control of the cantilever 13.

[0070] Figure 7 The diagram shows the angular velocity ω [° / s] of the cantilever 13 within an angle range of +90° to -90° during a right-to-left pivoting motion (Figure RL) or a left-to-right pivoting motion (Figure LR), and the torque curve M [kNm] for the same pivoting motion. It can be seen that the angular velocity ω is approximately constant throughout the pivoting range and increases only slightly in both directions with increasing pivot angle. Furthermore, the torque M applied by the piston / cylinder arrangement 18, 18' varies only insignificantly throughout the pivoting range. In this embodiment, the torque does not exceed 50 kNm. Because the pressure exerted by the fluid acts in both directions and no large torque occurs, the dimensions of the piston / cylinder arrangement 18, 18' can be relatively small.

Claims

1. A self-propelled milling machine having a machine frame (4) supported by a traveling mechanism (6A, 6B), a working device (5) disposed on the machine frame (4) for working on the ground, and a conveying device (12) for removing material, wherein the conveying device (12) has a cantilever (13) and a pivoting device (16) for pivoting the cantilever (13), the cantilever (13) being mounted on the machine frame (4) for pivoting about a rotation axis (X) substantially perpendicular to the machine frame, wherein the pivoting device (16) includes at least one linear drive (17A, 17B). Its features are: The pivoting device (16) includes at least one mechanism and at least one linear actuator (17A, 17B), the mechanism having multiple mechanism links (101, 102, 103, 104; 101', 102', 103', 104') and joints (A, B, C, D) connecting them, the linear actuator (17A, 17B) for driving at least one mechanism link, at least one mechanism of the pivoting device being designed as a planar four-bar pivot joint mechanism (16A, 16B), wherein the machine frame (4) forms the fourth mechanism link (104, 104') of the pivot joint mechanism, the first planar four-bar pivot joint mechanism (16A, 16B) A) and the second-plane four-bar pivot joint mechanism (16B) have a first mechanism link (101, 101'), one end of the first mechanism link (101, 101') is hinged to the machine frame (4) through a first joint (A), the other end of the first mechanism link (101, 101') is hinged to one end of the second mechanism link (102, 102') through a second joint (B), the other end of the second mechanism link (102, 102') is hinged to one end of the third mechanism link (103, 103') through a third joint (C), and the other end of the third mechanism link (103) is hinged to the machine frame (4) through a fourth joint (D).

2. The self-propelled milling machine according to claim 1, characterized in that, The pivoting device (16) has a first planar four-bar pivot joint mechanism (16A) and a second planar four-bar pivot joint mechanism (16B), wherein the first pivot joint mechanism and the second pivot joint mechanism are arranged in a mirror symmetric manner with respect to the longitudinal center plane of the machine frame (4).

3. The self-propelled milling machine according to claim 1, characterized in that, A first linear actuator (17A) is provided, having a first piston / cylinder arrangement (18), wherein a cylinder (18B) of the first piston / cylinder arrangement (18) is hinged at one end to one of the mechanism links of a first planar four-bar pivot mechanism (16A), and a piston (18A) of the first piston / cylinder arrangement (18) is hinged at one end to a machine frame (4), or a cylinder (18B) of the first piston / cylinder arrangement (18) is hinged at one end to a machine frame (4), and a piston (18A) of the first piston / cylinder arrangement (18) is hinged at one end to one of the mechanism links of the first four-bar pivot mechanism; and A second linear actuator (17B) is provided, having a second piston / cylinder arrangement (18'), wherein the cylinder (18B') of the second piston / cylinder arrangement (18') is hinged at one end to one of the mechanism links of a second planar four-bar pivot mechanism (16B), and the piston (18A') of the second piston / cylinder arrangement (18') is hinged at one end to a machine frame (4), or the cylinder (18B') of the second piston / cylinder arrangement (18') is hinged at one end to a machine frame (4), and the piston (18A') of the second piston / cylinder arrangement (18') is hinged at one end to one of the mechanism links of a second four-bar pivot mechanism.

4. The self-propelled milling machine according to claim 3, characterized in that, The piston or cylinder of the first piston / cylinder arrangement (18) is hinged at one end to the second mechanism link (102) of the first planar four-bar pivot joint mechanism (16A); and The piston or cylinder of the second piston / cylinder assembly (18') is hinged at one end to the second mechanism link (102') of the second planar four-bar pivot joint mechanism (16B).

5. The self-propelled milling machine according to claim 4, characterized in that, The second mechanism link (102) of the first planar four-bar pivot joint mechanism (16A) has a flange (102A), on which the piston or cylinder of the first piston / cylinder arrangement structure (18) is hinged at one end to the second mechanism link (102) of the first planar four-bar pivot joint mechanism (16A); and The second mechanism link (102') of the second planar four-bar pivot joint mechanism (16B) has a flange (102A'), on which the piston or cylinder of the second piston / cylinder arrangement structure (18') is hinged at one end to the second mechanism link (102') of the second planar four-bar pivot joint mechanism (16B).

6. The self-propelled milling machine according to any one of claims 1 to 5, characterized in that, The first mechanism link (101, 101') of the first planar four-bar pivot joint mechanism (16A) and the second planar four-bar pivot joint mechanism (16B) is formed by a flat bar, and the second mechanism link (102, 102') of the first planar four-bar pivot joint mechanism (16A) and the second planar four-bar pivot joint mechanism (16B) is formed by two spaced-apart flat bars, wherein one end of the bar of the first mechanism link (101, 101') is rotatably mounted between the ends of the two bars of the second mechanism link (102, 102').

7. The self-propelled milling machine according to any one of claims 1 to 5, characterized in that, The third mechanism link (103, 103') of the first planar four-bar pivot joint mechanism (16A) and the second planar four-bar pivot joint mechanism (16B) is formed by a bracket (15) mounted on the cantilever (13), wherein the bracket (15) is mounted on the machine frame (4) so ​​as to pivot about a rotation axis (X) located in the longitudinal center plane of the machine frame (4).

8. The self-propelled milling machine according to any one of claims 3 to 5, characterized in that, When the cantilever (13) is not pivoting, the angle α enclosed by the first piston / cylinder arrangement (18) and the second piston / cylinder arrangement (18') is between 40° and 80°.

9. The self-propelled milling machine according to any one of claims 1 to 5, characterized in that, When the cantilever (13) is not pivoting, the angle α enclosed by the first mechanism links (101, 101') of the first planar four-bar pivot joint mechanism (16A) and the second planar four-bar pivot joint mechanism (16B) is between 30° and 50°.

10. The self-propelled milling machine according to any one of claims 1 to 5, characterized in that, When the cantilever is not pivoting, the angle α enclosed by the second mechanism links (102, 102') of the first planar four-bar pivot joint mechanism (16A) and the second planar four-bar pivot joint mechanism (16B) is between 70° and 110°.

11. The self-propelled milling machine according to any one of claims 1 to 5, characterized in that, The first joints (A, A') of the first planar four-bar pivot joint mechanism (16A) and the second planar four-bar pivot joint mechanism (16B) are positioned spaced apart from each other in the transverse plane of the machine frame (4), the transverse plane of the machine frame (4) being perpendicular to the longitudinal center plane.

12. The self-propelled milling machine according to any one of claims 1 to 5, characterized in that, The third joints (C, C') of the first planar four-bar pivot joint mechanism (16A) and the second planar four-bar pivot joint mechanism (16B) form a common joint.

13. The self-propelled milling machine according to any one of claims 3 to 5, characterized in that, The milling machine has a hydraulic unit (20) for actuating a first piston / cylinder arrangement (18) and a second piston / cylinder arrangement (18'), the hydraulic unit (20) being designed such that, in a first operating mode, the piston (18A) of the first piston / cylinder arrangement (18) extends and the piston (18A') of the second piston / cylinder arrangement (18') retracts, thereby pivoting the cantilever (13) to one side, and in a second operating mode, the piston (18A) of the first piston / cylinder arrangement (18) retracts and the piston (18A') of the second piston / cylinder arrangement (18) extends, thereby pivoting the cantilever (13) to the other side.

14. The self-propelled milling machine according to claim 13, characterized in that, An operating unit (11) is provided, which interacts with a hydraulic unit (20) and has at least one operating element (11A), which interacts with the hydraulic unit (20) such that at least one operating element (11A) takes a first position for pivoting the cantilever (13) in one direction and a second position for pivoting the cantilever (13) in another direction.

15. The self-propelled milling machine according to any one of claims 1 to 5, characterized in that, A conveyor belt (35) is installed on the cantilever (13).

16. The self-propelled milling machine according to claim 1, characterized in that, The self-propelled milling machine is a road milling machine or an open-pit mining machine.

17. The self-propelled milling machine according to claim 8, characterized in that, When the cantilever (13) is not pivoting, the angle α enclosed by the first piston / cylinder arrangement (18) and the second piston / cylinder arrangement (18') is between 50° and 70°.

18. The self-propelled milling machine according to claim 9, characterized in that, When the cantilever (13) is not pivoting, the angle α enclosed by the first mechanism links (101, 101') of the first planar four-bar pivot joint mechanism (16A) and the second planar four-bar pivot joint mechanism (16B) is between 20° and 40°.

19. The self-propelled milling machine according to claim 10, characterized in that, When the cantilever is not pivoting, the angle α enclosed by the second mechanism links (102, 102') of the first planar four-bar pivot joint mechanism (16A) and the second planar four-bar pivot joint mechanism (16B) is between 80° and 100°.

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