Apparatus for connecting an implement to a work machine and method for monitoring a mechanical load of said apparatus

Abstract

An apparatus (1) for connecting an implement to a work machine has a pivoting device (2) by means of which an implement connecting device (4) can be pivoted relative to a work machine connecting device (3) about a pivot axis, wherein the pivoting device (2) has a hollow cylinder, a piston shaft which is mounted pivotably about the pivot axis in the hollow cylinder, and an annular piston sleeve which is mounted displaceably in an axial direction along the pivot axis between the hollow cylinder and the piston shaft. The piston shaft has, successively in the axial direction between the two radial bearings, an annular piston sleeve sliding section with a sliding section diameter and the piston shaft engagement section with an engagement section diameter (DE) which is greater than the sliding section diameter (DG). A torque measuring device is arranged on or in the piston shaft in the piston shaft engagement section, by means of which torque measuring device a torque characteristic variable for a torque acting on the piston shaft can be detected.

Description

[0001] Device for connecting a work tool to a

[0002] Working machine and method for monitoring a mechanical load on this device

[0003] The invention relates to a device for connecting a work tool to a work machine, wherein the device comprises a work machine connection device for connection to the work machine, a work tool connection device for connection to the work tool, and a pivoting device with which the work tool connection device is pivotable relative to the work machine connection device about a pivot axis, wherein the pivoting device comprises a hollow cylinder, a piston shaft pivotably mounted in the hollow cylinder about a pivot axis, and an annular piston sleeve mounted between the hollow cylinder and the piston shaft in an axial direction along the pivot axis.the annular piston sleeve is positively engaged with the surrounding hollow cylinder via a sleeve cylinder engagement section and is connected via a sleeve piston engagement section to a piston shaft engagement section adapted thereto in a rotationally fixed engagement such that a forced axial displacement of the annular piston sleeve causes a pivoting movement of the piston shaft, which is pivotably mounted in the hollow cylinder, relative to the hollow cylinder, wherein the piston shaft is rotatably mounted in the hollow cylinder via two radial bearings spaced apart from each other in the axial direction, and wherein the piston shaft has, successively in the axial direction between the two radial bearings, an annular piston sleeve sliding section with a sliding section diameter and the piston shaft engagement section with an engagement section diameter that is larger than the sliding section diameter.

[0004] Devices of this kind, which allow a work tool to be pivotably attached to a machine and used on the machine for its respective purpose, are suitable and known for a wide variety of applications. The machine can be, for example, a construction machine such as an excavator, and the work tool can be a tool or an interchangeable attachment such as an excavator bucket. Such a connecting device with a swivel mechanism can also be a component of a truck-mounted crane or a container crane, a machine tool, a machining system, or even a component of a process automation system.The machine connection device and the implement connection device are each suitably designed and constructed in such a way that a reliable and sufficiently mechanically robust connection of the machine and implement to the device is possible and that a fastening process as well as any possible detachment and replacement process can be carried out quickly and reliably.

[0005] The swivel device described above is characterized by its highly reliable operation, enabling the transmission of high forces and torques during operation. An exemplary embodiment of such a swivel device is shown and described, for example, in DE 1 426 525 A1. The axial displacement of the annular piston sleeve is typically achieved hydraulically or with the aid of electric motors. Particularly when the device is used in construction machinery such as an excavator, the swivel device can be integrated into the machine's drive system and, for example, actuated by a hydraulic system that is also used to operate the machine.

[0006] In the pivoting device shown in DE 1 426 525 A1, the annular piston sleeve has a first steep thread engagement with the piston shaft engagement section of the piston shaft and a second steep thread engagement with an oppositely directed steep thread angle with the hollow cylinder surrounding the annular piston sleeve. In this way, large pivot angles between the piston shaft and the hollow cylinder can be achieved and large torques can be transmitted by a forced axial displacement of the annular piston sleeve.

[0007] It is known from practice that during the intended use of the device as a component of, for example, a construction machine, an unintentionally large mechanical load on the work tool or machine, or an excessive force, may occur, which could potentially lead to overloading and damage to the device or the components attached to it.From DE 10 2022 132 871 B3, for example, it is known that a pressure relief valve is provided in a hydraulically operated rotary drive, which is opened in the event of an increase in the pressure of a hydraulic fluid in the hydraulic line used for actuating the rotary drive, and that the rotary drive is designed without a self-locking mechanism, so that a working device connected to the working machine via the rotary drive can be rotated freely and thus, in most cases, excessive mechanical stress and damage can be avoided.

[0008] From US 2018 / 0073945 A1, it is known to measure the forces acting on a hydraulically actuated cylinder piston in a hydraulically operated construction machine. A comparable approach is described, for example, in DE 10 2018 112 723 A1 of fenbart. Measuring forces acting on a hydraulic cylinder or other components of a hydraulic system is complex and only allows for an indirect determination of the mechanical load exerted on the device, and in particular on the swivel mechanism.

[0009] It is considered an object of the present invention to design a measuring device in such a way that an impending excessive stress on the swiveling device of the apparatus can be detected and monitored as reliably as possible with the least possible effort.

[0010] This problem is solved according to the invention by arranging a torque measuring device on or in the piston shaft in the piston shaft engagement section, with which a torque parameter for a torque acting on the piston shaft can be detected. Since the piston shaft engagement section has a larger engagement section diameter than the sliding section diameter of the annular piston sleeve sliding section, the piston shaft engagement section forms a stiffer region of the piston shaft, over which a greater proportion of the forces and torques exerted on the piston shaft are transferred.In comparison to an arrangement of the torque measuring device in the ring piston sleeve sliding section of the piston shaft, a torque measuring device arranged on or in the piston shaft engagement section of the piston shaft can detect a larger proportion of the torques exerted on the piston shaft and therefore a potential overload can be better estimated.

[0011] The torque measuring device can continuously or at short intervals record torque parameters and compare these actual values ​​with a threshold value, which, for example, was determined and defined beforehand or determined and specified through simulations. If, in individual cases, the device, and in particular its swivel mechanism, is unintentionally damaged, the torque parameters recorded immediately before the damage, or the torque parameter trends over the period immediately preceding the damage, can be used to determine which torques caused the damage.

[0012] The piston shaft engagement section is defined as the portion of the piston shaft which, compared to the sliding section diameter of the piston shaft in the annular piston sleeve sliding section, has a engagement section diameter larger than the sliding section diameter. The piston shaft engagement section typically extends axially over an engagement area with a positive engagement with the annular piston sleeve to an associated end face of the piston shaft that is located a shorter distance from the engagement area. Similarly, the annular piston sleeve sliding section of the piston shaft extends axially to the end face of the piston shaft associated with the annular piston sleeve sliding section of the piston shaft that is located a greater distance from the engagement area of ​​the piston shaft.In many cases, an arrangement of the torque measuring device that overlaps the engagement area in the axial direction can be advantageous.

[0013] However, it may also be provided that the torque measuring device is arranged in the immediate vicinity of the end face of the piston shaft associated with the piston shaft engagement section, between positively engaged engagement elements on the one hand and this end face on the other, and thus, for example, in an area of ​​a bearing device in which no positive engagement is formed.

[0014] Due to the positive engagement between the piston sleeve engagement section of the annular piston sleeve on the one hand and the piston shaft engagement section of the piston shaft on the other, a distance is regularly defined in this area between the positive engagement and an end face of the piston shaft associated with the piston shaft engagement section, regardless of the piston shaft diameter. This distance is shorter than the distance between this positive engagement and the opposite end face associated with the annular piston sleeve sliding section. Because of the shorter length between the end face and the positive engagement, the piston shaft engagement section is typically more torsionally rigid than the annular piston sleeve sliding section of the piston shaft. Therefore, for this reason as well, the arrangement of the torque measuring device in the piston shaft engagement section is advantageous.

[0015] For many applications, it is considered advantageous to have a steep thread engagement between the annular piston sleeve and the piston shaft in the engagement section, and also a steep thread engagement between the annular piston sleeve and the surrounding hollow cylinder. However, configurations of the pivoting device are also conceivable in which either a positive engagement between the hollow cylinder and the annular piston sleeve or a positive engagement between the annular piston sleeve and the piston shaft is not a steep thread engagement, but rather a twisted positive engagement with, for example, axially extending serrations.For example, the swiveling device can also be designed in such a way that the ring piston sleeve is axially displaceable in the piston shaft engagement section and is connected to the piston shaft in a rotationally stable manner with the aid of a suitable positive guide, while a steep thread engagement used for the swiveling movement is formed between the ring piston sleeve and the surrounding hollow cylinder.

[0016] The annular piston sleeve sliding section typically has a cylindrical surface with a uniform sliding sleeve diameter. The diameter of the piston shaft engagement section is regularly larger so that, due to the larger diameter, the externally arranged engagement elements and the moments acting upon them have the largest possible lever arm relative to the pivot axis, thereby enabling the reliable absorption and transmission of higher torques. The respective diameter is determined along the axial direction as the distance between opposing regions of a cylindrical surface that circumferentially rests against and encloses the piston shaft.For example, the engagement section diameter of the piston shaft engagement section in a region with a radially outwardly projecting steep thread is the nominal diameter of the steep thread, and in a region without a radially outwardly projecting steep thread, it is the diameter of the cylindrically shaped piston shaft in this region. Regardless of the design and arrangement of the positive engagement between the annular piston sleeve and the piston shaft, the section of the piston shaft with the larger diameter is considered and designated as the piston shaft engagement section, even if the positive engagement is located in a section of the piston shaft with a smaller diameter, so that, according to the invention, the torque measuring device is always located in an axial section of the piston shaft with a larger diameter than in an opposite section.

[0017] The section is arranged with a smaller diameter.

[0018] For detecting and monitoring excessive torque loads, a torque measuring device arranged on or in the piston shaft engagement section of the piston shaft is sufficient. In this way, the torque exerted on the piston shaft during operation can be continuously detected with minimal manufacturing and evaluation effort. According to one embodiment of the invention, it is therefore also provided that the device contains only a single torque measuring device arranged on or in the piston shaft engagement section of the piston shaft, and that only this torque measuring device detects and monitors the impending excessive stress on the pivoting mechanism of the device.

[0019] The measured values ​​acquired by the torque measuring device, which correlate with the torque exerted on the piston shaft, can be continuously compared with a torque threshold during operation. A warning signal can be triggered if the measured values ​​exceed the torque threshold, thus indicating an impending overload of the piston shaft and consequently of the swivel mechanism or the entire device. It is also possible to save the measured values ​​acquired by the torque measuring device and, if necessary or at regular intervals, to evaluate the stored data in order to, for example, identify load peaks and to assess increasing material fatigue or an impending failure of the swivel mechanism.

[0020] According to a particularly advantageous embodiment of the invention, the piston shaft has a measuring recess on an end face facing the piston shaft engagement section. This recess extends axially into the piston shaft engagement section, and the torque measuring device is arranged and fixed in this recess so that the torque can be measured. By arranging the torque measuring device in the measuring recess, it is protected during operation by the surrounding areas of the piston shaft. Furthermore, the torque measuring device can be advantageously arranged and fixed in the recess in such a way that the torques acting on the piston shaft can be measured precisely.

[0021] Optionally, the torque measuring device includes a deformation body with a deformation zone and a sensor device located within that zone. The deformation body is force-transmittingly fixed in the measuring recess, allowing the sensor device to detect mechanical stresses transmitted to the deformation body by the piston shaft and the resulting deformation of the body's deformation zone. Suitable deformation bodies are available in various designs and combinations with different sensor devices, enabling the torque measuring device to be procured cost-effectively and installed in the piston shaft.

[0022] Advantageously, it is optionally provided that an elastically deformable press-fit element is arranged at each of two opposite ends of the deformation body, so that the press-fit element adapts to an inner wall of the measuring recess and is pressed firmly against the inner wall, thereby transferring a mechanical stress from the piston shaft to the deformation body via the press-fit elements and causing a deformation of the deformation area of ​​the deformation body that can be detected by the sensor device. A torque measuring device designed in this way is disclosed, for example, in EP 4 185 850 A1. Such a torque measuring device can also be inserted into a recess not designed as a precision bore with minimal assembly effort and reliably fixed in such a way that the moments acting on the piston shaft can be transferred to the deformation body and reliably and precisely detected there by the sensor device.

[0023] According to an advantageous embodiment of the invention, the torque measuring device can further be arranged in an axial direction at least partially overlapping with a radial bearing of the piston shaft. In the area of ​​a radial bearing, the piston shaft expediently has a radially projecting and particularly deformation-resistant ridge or flange, so that this area of ​​the piston shaft absorbs a particularly high proportion of the forces and torques exerted on it. This makes the measured values ​​acquired by the torque measuring device particularly meaningful and allows for reliable detection and monitoring of the torque exerted on the piston shaft.

[0024] Optionally, in addition to the torque measuring device in the annular piston sleeve sliding section of the piston shaft, a first auxiliary measuring device may be arranged on or in the piston shaft. This auxiliary measuring device allows for the acquisition of a first auxiliary parameter for forces and / or torques acting on the piston shaft. By using an auxiliary measuring device and arranging it in a different area of ​​the piston shaft, which has a different stiffness due to its sliding section diameter differing from and being smaller than that of the piston shaft engagement section, an auxiliary parameter for a torque acting on the piston shaft can be acquired. This auxiliary parameter can then be used to support, control, and, if necessary, improve the evaluation of the torque parameter acquired by the torque measuring device.For example, a correlation between the auxiliary parameters recorded by the auxiliary measuring device and the torque parameters recorded by the torque measuring device can be determined in advance for a number of predefined torques and stored in a characteristic map or in a parameter set for a correlation function in order to monitor the torque parameter recorded by the torque measuring device during operation based on the auxiliary parameters recorded by the auxiliary measuring device and to avoid or at least identify any malfunctions or disturbances in the recording of the torque parameter and the monitoring of a load on the piston shaft.It is also conceivable that, with the auxiliary measuring device and the auxiliary parameters recorded by the auxiliary measuring device, the influence of the ring piston sleeve, which may shift axially, and thus of the thread engagement between the ring piston sleeve and the piston shaft, can be detected and taken into account when determining a torque acting on the piston shaft, since an axial displacement of the ring piston sleeve and thus of the positive engagement with the piston shaft can lead to a change in the stiffness of the piston shaft in the piston shaft engagement section.

[0025] It is also conceivable that the auxiliary measuring device could detect forces acting on the piston shaft. In this way, in addition to the mechanical load caused by torque, unexpected shock loads or tensile and compressive forces exerted on the piston shaft in addition to torque could also be detected.

[0026] The auxiliary measuring device can comprise one or more sensors spaced apart from each other on or in the piston shaft. The sensors can be designed, configured, and arranged such that they can detect either moments or forces, or both, acting on the piston shaft.

[0027] According to a further embodiment of the invention, a fixing device for securing the hollow cylinder to the machine or tool is arranged on an outer surface of the hollow cylinder, and a second auxiliary measuring device is arranged on or in the fixing device, with which at least one second auxiliary parameter for forces and / or moments acting on the hollow cylinder can be detected. With such a second auxiliary measuring device, moments or forces acting on the fixing device of the hollow cylinder of the pivoting device, in which the piston shaft is pivotably mounted, can also be detected. By a suitable arrangement and design of the second auxiliary measuring device, additional information about the mechanical loads occurring in the device during operation of the machine can be acquired.This information can be used, for example, to identify and, if necessary, differentiate between various causes of gradual or sudden damage to the device. It can also be used to record and analyze the loads expected to occur during operation over a longer period, in order to improve the design and dimensioning of the entire device as well as individual components.

[0028] With a view to the most comprehensive possible evaluation of the torque parameters, which may be recorded over a longer period, it may be advantageous, according to a further aspect of the invention, for the device to have a transmission device for transmitting the torque parameters recorded by the torque measuring device for a torque acting on the piston shaft to an evaluation device. The transmission device can be designed and configured such that auxiliary parameters and secondary auxiliary parameters, if any, can also be transmitted to the evaluation device. Transmission can be provided either continuously, at time intervals, or only when needed and activated accordingly. Data transmission can be wired or wireless.The transmission device can optionally be designed and configured so that, in the event of an impending or already detected mechanical overload of the device, a warning signal or an alarm signal is transmitted to one or more recipients, for example as a message via the mobile network or the Internet.

[0029] It can also be advantageous for the device to have a storage unit for storing a number of torque parameters successively acquired by the torque measuring device for a torque acting on the piston shaft. The storage unit can, for example, be designed to provide sufficient storage capacity for storing torque parameters over an extended period of intended use of the device. The torque parameters acquired by the torque measuring device can then be fully stored in the storage unit and read out and evaluated as needed or at regular intervals.

[0030] A comprehensive evaluation of the recorded moment parameters is then possible even without a dedicated transmission device and without continuous transmission of the moment parameters to an evaluation unit. This is particularly advantageous if continuous or reliable transmission of the recorded moment parameters via the transmission device is not possible, for example, because a data transmission connection from the transmission device to the evaluation unit cannot be established.The storage device can also store comprehensive information about specific events or times, so that, for example, in the event of an impending or actual overload of the device, in addition to the moment parameters, further data such as the time, further parameters or specifications for the operation of the device and the associated machine and tool, or time-relevant auxiliary parameters or secondary auxiliary parameters can be recorded and made available for later evaluation.

[0031] According to a particularly advantageous embodiment of the invention, the device comprises a rotation device with which the working tool connection device is rotatable about an axis of rotation relative to the working machine connection device, wherein the rotation device comprises a worm gear with a driveable worm shaft having an external thread and with a worm wheel rotatably mounted about the axis of rotation, which meshes with the external thread of the worm shaft, wherein the worm shaft is rotatably mounted and axially fixed along a worm shaft axis extending transversely to the axis of rotation in a first bearing device arranged along the worm shaft axis at a distance from the external thread, wherein the rotation device comprises a drive device which is operatively connected to a drive section of the worm shaft.and with which the worm shaft can be driven to a rotational movement about the worm shaft axis, wherein in a measuring section of the worm shaft between the first bearing device and the external thread a force measuring device for recording force parameters for axial forces exerted on the measuring section of the worm shaft and directed in an axial direction along the worm shaft axis is arranged on or in the worm shaft.

[0032] Particularly in construction machinery such as excavators, attachments like a bucket are advantageously fixed to one end of the excavator's boom using a swivel mechanism and a rotary mechanism, allowing the bucket to be swiveled and rotated around the end of the boom. In conjunction with a movable boom, the bucket then exhibits many degrees of freedom for movement relative to the excavator's base. Rotary mechanisms with the aforementioned features, or with a worm gear and a driven worm shaft, are well-known in practice and have proven highly effective, particularly in construction machinery.For the mechanical loads on a rotating device and their effects on its current use, as well as on gradually increasing fatigue and wear, other parameters are relevant that cannot be readily detected or reliably estimated using a torque measuring device in the rotary mechanism. It has been shown that any potential overload of the rotating device can be reliably detected and monitored with minimal effort by arranging the force measuring device used for this purpose at a suitable location on or in the worm shaft, enabling it to detect at least the axial forces directed along the worm shaft axis.A suitable arrangement and mounting of the force measuring device between the first bearing assembly and the external thread of the worm shaft is easily achievable and allows for protected positioning of the force measuring device in a region of the worm shaft where axial forces acting on the worm shaft can be reliably and precisely measured. In this way, both obstructions during a rotational movement of the rotating device during operation and externally acting torques can be detected. These torques can act on the rotating device if it is fixed in rotation during operation, thereby exerting an additional torque on the rotating device.

[0033] The worm shaft preferably has a single-start external thread with a self-locking effect. However, it is also conceivable that the worm shaft has a multi-start external thread and, additionally or instead of a self-locking effect, a braking device with which rotational movement of the worm shaft can be hindered or completely prevented, for example, if the working tool is to be held and fixed in a predetermined orientation relative to the machine.

[0034] Additional measuring devices may be provided, but are not strictly necessary in practice for detecting and monitoring any potential overload of the rotating device. According to one embodiment of the invention, it is therefore also provided that only a single force measuring device is arranged on or in the measuring section of the worm shaft in the device, and that only with this force measuring device is the impending excessive stress on the rotating device of the apparatus detected and monitored.

[0035] According to an advantageous embodiment of the invention, the worm shaft has a measuring recess extending along the axis of the worm shaft in the direction of the external thread on an end face facing away from the external thread. The force measuring device is arranged and fixed in this recess so that tensile and / or compressive forces exerted on the worm shaft can be detected. It has been shown that arranging the force measuring device in a recess accessible from the end face of the worm shaft allows for a comparatively precise measurement of the axial forces acting on the worm shaft, and the force measuring device is protected from mechanical stress within the recess. Various designs of force measuring devices are known from practical experience that can be manufactured cost-effectively and fixed in the recess.The arrangement within the recess eliminates the need for additional installation space for the force measuring device in the area surrounding the worm gear. According to a further aspect of the invention, the worm shaft can be rotatably mounted in a second bearing on the side of the external thread opposite the first bearing. The second bearing provides positive guidance for the worm shaft, enabling transverse forces acting perpendicular to the worm shaft axis to be absorbed by the two bearings. This allows the force measuring device to detect essentially axial forces without unduly influencing or distorting the axial force measurements.

[0036] For many applications, it can be advantageous for the force measuring device to include a sensor and a power supply unit that provides electrical energy to the sensor. For the operation of the rotary device, it is often beneficial that the worm shaft can not only be pivoted around its axis over a certain angular range, but also that it can rotate continuously in one direction or the opposite direction around its axis and be driven accordingly. The force measuring device can use a battery as its power supply unit to power the sensor. However, with prolonged use of the rotary device, it is then necessary to replace or recharge the battery at intervals.Advantageously, the power supply unit may include a power transmission device with which electrical energy can be transmitted wirelessly, i.e., without a continuous electrical conductor, from a power supply unit to the measuring recess of the worm shaft, which is rotatably mounted in the bearing assembly. The electrical energy can, for example, be transferred by induction from an energy storage unit outside the worm shaft to the force measuring device on or in the worm shaft. It is also conceivable that the electrical energy is transferred to the rotating worm shaft via brush contacts or friction contacts.

[0037] The invention also relates to a method for monitoring the mechanical load on a device for connecting a working tool to a machine, wherein the device has one of the previously described combinations of features. According to the invention, a torque parameter detected by the torque measuring device for a torque acting on the piston shaft is transmitted to an evaluation device, and the evaluation device checks whether the torque parameter is less than or greater than a predefinable torque parameter threshold. The evaluation device can be arranged in the device itself, so that the evaluation of the detected torque parameters can be carried out in the device itself. The evaluation device can also be arranged on or in the machine and, optionally, also on or in the working tool to which the device is connected.Alternatively or additionally, the evaluation unit can also be located externally and transmit momentary parameters to the external evaluation unit continuously or at time intervals, where they can be evaluated.

[0038] Furthermore, it can be advantageously provided that a number of the torque parameters successively recorded by the torque measuring device for a torque acting on the piston shaft are transmitted to a storage device and stored there. The storage device can also be arranged on or in the device, or it can be an external storage device to which the torque parameters must be transmitted continuously or at time intervals.

[0039] The following section explains various embodiments of the inventive concept in more detail, which are illustrated by way of example in the drawings. It shows:

[0040] Fig. 1 shows a perspective view of a device for connecting a work tool to a work machine, where the work machine can be a construction machine.

[0041] Fig. 2 shows a perspective view of the device shown in Fig. 1, which is arranged by way of example on a bucket arm of a hydraulic excavator and is designed and intended, for example, for connection with a bucket or other working equipment.

[0042] Fig. 3 shows a perspective view of a hollow cylinder and a piston shaft pivotably mounted therein, which in the device shown in Figs. 1 and 2 are components of a pivoting device of the device; Fig. 4 shows a sectional view through the hollow cylinder shown in Fig. 3 with the piston shaft mounted therein and an annular piston sleeve that can be displaced in an axial direction between the piston shaft and the hollow cylinder.

[0043] Fig. 5 shows a perspective view of the piston shaft shown in Figs. 3 and 4 with a piston shaft engagement section and with a ring piston sleeve sliding section.

[0044] Fig. 6 shows a side view of the piston shaft shown in Fig. 5,

[0045] Fig. 7 shows a perspective view of a rotating device that can be integrated into a device according to Fig. 1.

[0046] Fig. 8 shows a sectional view of the rotary device shown in Fig. 7 with a rotatably mounted worm wheel and a worm shaft meshing with the worm wheel.

[0047] Fig. 9 shows a perspective view of a combination of the rotary device shown in Figs. 7 and 8 with the hollow cylinder and the piston shaft pivotably mounted therein, as shown in Figs. 3 and 4.

[0048] Fig. 10 shows a sectioned view of the combination shown in Fig. 9 and Fig. 11 shows a perspective view of a device with a swiveling device and a rotating device.

[0049] A device 1, shown in Fig. 1, for connecting a working tool to a machine has a pivoting device 2. The pivoting device 2 has a machine connection device 3 on one side, shown at the top in Fig. 1, for connecting to the machine. On the opposite side, the pivoting device 2 has a working tool connection device 4 for connecting to the working tool (not shown in detail). The working tool connection device 4 is pivotably connected to the machine connection device 3 by the pivoting device 2 and is pivotably mounted thereon.

[0050] The machine connection device 3 is designed such that the device 1 with the machine connection device 3 can be fixed to an outer end 5 of a lever arm 6, also referred to as a bucket handle, of a machine shown by way of example as construction machine 7 in Fig. 2. A bucket or another work implement can be interchangeably fixed to the implement connection device 4, so that the construction machine 7 offers different usage options depending on the work implement connected to it and can, for example, be used with a bucket as a backhoe or with a stone milling machine. The pivoting device 2 shown in Fig. 1 has a hollow cylinder 8 and a piston shaft 10 pivotably mounted therein about a pivot axis 9 extending in an axial direction, which are shown separately in Figs. 3 and 4.The piston shaft 10 is supported in the hollow cylinder 8 by two radial bearings 11, which are arranged at opposite ends of the piston shaft 10. The radial bearings 11 also provide axial support and prevent axial displacement of the piston shaft 10 relative to the surrounding hollow cylinder 8 during operation. An annular piston sleeve 12 is arranged between the piston shaft 10 and the hollow cylinder 8, which surrounds the piston shaft 10 radially. The annular piston sleeve 12 is supported at an end face 13 by a sliding ring 14 on an annular piston sleeve sliding section 15 of the piston shaft 10. At an opposite end, the annular piston sleeve 12 has a sleeve piston engagement section 16 with an inwardly formed steep thread, which engages with a corresponding outwardly formed steep thread in a piston shaft engagement section 17 of the piston shaft 10.The ring piston sleeve 12 engages with the surrounding hollow cylinder 8 via a further positive locking engagement in a sleeve cylinder engagement section 44.

[0051] The annular piston sleeve 12, through the sliding ring 14 and a fluid-tight annular seal 18, divides a hollow cylindrical cavity 19, which surrounds the piston shaft 10 between the two radial bearings 11, into two fluid-filled pressure chambers 20, 21. These chambers can be alternately pressurized, thereby forcing an axial displacement of the annular piston sleeve 12. The steep thread engagement between the sleeve piston engagement section 16 and the piston shaft engagement section 17 converts this forced axial displacement of the annular piston sleeve 12 into a pivoting movement of the piston shaft 10, which engages the annular piston sleeve 12 via the steep thread engagement. In this way the piston shaft 10 can be pivoted relative to the hollow cylinder 8 and thereby a corresponding pivoting movement of the working tool connection device 4 relative to the working machine connection device 3 can be effected.

[0052] The annular piston sleeve sliding section 15 of the piston shaft 10 has a sliding section diameter DG. The piston shaft engagement section 17 of the piston shaft 10 has an engagement section diameter DE. The sliding section diameter DG is smaller than the engagement section diameter DE. For this reason, the stiffness of the piston shaft 10 in the piston shaft engagement section 17 of the piston shaft 10 is greater than in the annular piston sleeve sliding section 15 of the piston shaft 10.

[0053] During the intended use of the device 1, torques act on the piston shaft 10. The intended use of the device 1 is expediently limited to movements and loads that are considered safe for the device 1 and do not regularly represent excessive stress on the device 1. However, it cannot be ruled out, and occasionally occurs in practice, that, for example, during normal use of the device 1 in a construction machine 7 for moving a bucket, the bucket encounters an unexpected obstacle that hinders the continuation of the intended movement sequence for the bucket, thereby causing an unexpectedly high mechanical load on the device 1.

[0054] To monitor undesirable excessive stress on the device 1 and, if necessary, to warn of an impending overload, a torque measuring device 24 is arranged and fixed in a recess 23 in the piston shaft 10, accessible from an end face 22, such that the torque measuring device 24 can detect torque parameters that correlate with a torque exerted on the piston shaft 10. Since the torque measuring device 24 is arranged in the piston shaft engagement section 17 of the piston shaft 10, which has a higher stiffness than the opposing annular piston sleeve sliding section 15 of the piston shaft 10, this arrangement of the torque measuring device 24 allows for the detection of torque parameters that enable a more precise and reliable determination of the torques exerted on the piston shaft 10.

[0055] It may optionally be provided that, additionally spaced apart from the recess 23 containing the torque measuring device 24, a first auxiliary measuring device 26 is arranged in an area 25 in the annular piston sleeve sliding section 15 on or in the piston shaft 10, which is only indicated by way of example in Fig. 4. This auxiliary measuring device allows a first auxiliary parameter for forces and / or torques acting on the piston shaft 10 to be detected. Due to the different stiffness of the piston shaft 10 in the annular piston sleeve sliding section 15 compared to the piston shaft engagement section 17 of the piston shaft 10, the torque parameters detected by the torque measuring device 24 and by the first auxiliary measuring device 26 will differ. first auxiliary parameters differ, even if the torque measuring device 24 and the first auxiliary measuring device 26 are identically designed and set up and are arranged and fixed in a comparable manner in the piston shaft 10.By conducting preliminary reference measurements with a reference piston shaft 10, a characteristic map with torque parameters and initial auxiliary parameters can be determined if required, and a correlation between the torque parameters and the initial auxiliary parameters can be established. In this way, the initial auxiliary parameters can be used to check the plausibility and error-free acquisition of corresponding torque parameters. It is also possible to improve the precision and accuracy in determining the actual torque acting on the piston shaft 10 by considering the initial auxiliary parameters, and thus to make the monitoring of an impending or already occurring overload of the piston shaft 10 and consequently of the pivoting device 2 more reliable.

[0056] It may additionally be provided that a fixing device 28 for fixing the hollow cylinder 8 to the working machine or to the working device is arranged on an outer lateral surface 27 of the hollow cylinder 8, and that a second auxiliary measuring device 29, shown only schematically in Fig. 3, is arranged on or in the fixing device 28, with which at least a second auxiliary parameter for forces and / or moments acting on the hollow cylinder 8 can be detected.

[0057] Figures 5 and 6 each show a view of the piston shaft 10 with the annular piston sleeve sliding section 15 and the piston shaft engagement section 17 for illustrative purposes. In the piston shaft engagement section 17, the piston shaft 10 has an outwardly formed steep thread, which engages with the corresponding inwardly formed steep thread of the sleeve steep thread section 16 of the annular piston sleeve 12 (not shown). The sliding section diameter DG is smaller than the engagement section diameter DE.

[0058] Figures 7 and 8 show a perspective view and a sectional view of a rotary device 30. The rotary device 30 has a worm gear 31, which is rotatably mounted in a rotary device housing 32 about a rotation axis 33 of the worm gear 31. A worm shaft 34 is also arranged in the rotary device housing 32 and is rotatably mounted about a worm shaft axis 35 in a first bearing arrangement 36 and in a second bearing arrangement 37 spaced apart from it. The worm shaft 34 has an external thread 38, which has one thread and is self-locking.The external thread 38 is spaced apart from the first bearing assembly 36 and arranged between the first bearing assembly 36 and the second bearing assembly 37. It is positioned and adapted to the worm gear 31 such that the external thread 38 meshes with the worm gear 31 on a circumferential surface, so that a rotational movement of the worm shaft 34 causes a rotational movement of the worm gear 31 about the axis of rotation 33. The worm shaft 34 can be driven by means of a drive device 39, which is operatively connected to the worm shaft 34, and can be selectively set into rotational movements in either direction about the worm shaft axis 35.

[0059] In a measuring section 40 of the worm shaft 34, which is arranged axially along the worm shaft axis 35 between the first bearing assembly 36 and the external thread 38, a recess 41 is formed which is accessible from an end face 42 of the worm shaft 34. A force measuring device 43 is arranged in this recess 41 and is fixed in such a way that force parameters for axial forces exerted on the measuring section 40 of the worm shaft 34 and directed in the axial direction along the worm shaft axis 35 can be recorded with this force measuring device 43.The meshing engagement between the external thread 38 of the worm shaft 34 and the worm wheel 31 generates an axial force acting on the worm wheel 31 via the external thread 39 through a torque acting transversely to the axis of rotation 33, whereby a force parameter for a tensile or compressive force exerted on the worm shaft 34 in the measuring section 40 can be recorded with the force measuring device 43.

[0060] The force measuring device 43 comprises a sensor device (not shown in detail in the figures) and a power supply device (also not shown in detail) that supplies the sensor device with electrical energy. The power supply device includes a power transmission device by which electrical energy can be wirelessly transmitted from a power supply device to the measuring recess 41 of the worm shaft 34, which is rotatably mounted in the first and second bearing arrangements 36, 37.

[0061] In Figures 9 and 10, the hollow cylinder 8 with the piston shaft 10 mounted therein, as shown in Figures 3 and 4, is mounted on the rotary device 30 shown in Figures 7 and 8. With the torque measuring device 24 arranged in the piston shaft 10 of the swiveling device 2 and the force measuring device 43 arranged in the worm shaft 34 of the rotary device 30, torque and force parameters for forces and moments exerted on the device 1 can be reliably recorded, and thus the mechanical load on the device 1 can be determined and monitored.

[0062] Figure 11 shows the device 1 with the machine connection device 3 for connecting to the machine, the implement connection device 4 for connecting to an implement, the pivoting device 2 arranged between the machine connection device 3 and the implement connection device 4, and the rotation device 30 also arranged between the machine connection device 3 and the implement connection device 4. With this device 1, for example, a bucket fixed to the implement connection device 4 and connected via the device 1 to the bucket arm of a construction machine 7 designed as an excavator can be aligned in almost all directions and moved over the bucket arm within a large working range.With the moment measuring device 24 and the force measuring device 43, a mechanical load on the device 1 and thus on the bucket and the construction machine 7 can be detected and monitored during the use of the construction machine 7.

Claims

P A T E N T A N S P R Ü C H E 1. Device (1) for connecting a working tool to a working machine, wherein the device comprises a working machine connection device (3) for connection to the working machine, a working tool connection device (4) for connection to the working tool and a pivoting device (2) with which the working tool connection device (4) is pivotable relative to the working machine connection device (3) about a pivoting axis (9), wherein the pivoting device (2) comprises a hollow cylinder (8), a piston shaft (10) pivotably mounted in the hollow cylinder (8) about the pivoting axis (9) and an annular piston sleeve (12) mounted between the hollow cylinder (8) and the piston shaft (10) so as to be displaceable in an axial direction along the pivoting axis (9),which engages with the surrounding hollow cylinder (8) via a sleeve cylinder engagement section (44) in a form-fitting manner and with a piston shaft engagement section (17) of the piston shaft (10) adapted thereto via a sleeve piston engagement section (16), so that a forced axial displacement of the ring piston sleeve (12) causes a pivoting movement of the piston shaft (10) pivotably mounted in the hollow cylinder (8) relative to the hollow cylinder (8), wherein the piston shaft (10) is connected via two axially spaced-apart radial bearing (11) is rotatably mounted in the hollow cylinder (8) and wherein the piston shaft (10) is in the axial direction successively between the two radial bearings (11) a ring piston sleeve sliding section (15) with a having a sliding section diameter (DG) and a piston shaft engagement section (17) with an engagement section diameter (DE) that is larger than the sliding section diameter (DG), characterized in that a torque measuring device (24) is arranged in the piston shaft engagement section (17) on or in the piston shaft (10), with which a torque parameter for a torque acting on the piston shaft (10) can be detected.

2. Device (1) according to claim 1, characterized in that the piston shaft (10) has a measuring recess (23) extending axially into the piston shaft engagement section (17) on an end face (22) facing the piston shaft engagement section (17), in which the torque measuring device (24) is arranged and fixed in such a way that a torque parameter for a torque acting on the piston shaft (10) can be detected with the torque measuring device (24).

3. Device (1) according to claim 2, characterized in that the torque measuring device (24) has a deformation body which has a deformation area and a sensor device which is fixed in the deformation area, and that the deformation body is force-transmittingly fixed in the measuring recess (23) so that a mechanical stress transmitted to the deformation body due to the mechanical stress of the piston shaft (10) and thereby forced deformation of the The deformation area of ​​the deformation body can be detected by the sensor device.

4. Device (1) according to claim 3, characterized in that an elastically deformable press-in element is arranged at each of two opposite ends of the deformation body, such that the press-in element adapts to an inner wall of the measuring recess (23) and is pressed forcefully against the inner wall and thereby a mechanical stress of the piston shaft (10) is transferred to the deformation body via the press-in elements and causes a deformation of the deformation area of ​​the deformation body that can be detected by the sensor device.

5. Device (1) according to one of the preceding claims, characterized in that the torque measuring device (24) is arranged in the axial direction at least partially overlapping with a radial bearing (11) of the piston shaft (10).

6. Device (1) according to one of the preceding claims, characterized in that, in addition to the torque measuring device (24) in the ring piston sleeve sliding section (15) of the piston shaft (10), a first auxiliary measuring device (26) is arranged on or in the piston shaft (10), with which a first auxiliary characteristic parameter for forces and / or torques acting on the piston shaft (10) can be detected.

7. Device (1) according to one of the preceding claims, characterized in that a fixing device (28) for fixing the hollow cylinder (8) to the working machine is provided on an outer lateral surface (27) of the hollow cylinder (8). or are arranged on the working device, and that a second auxiliary measuring device (29) is arranged on or in the fixing device (28), with which at least a second auxiliary characteristic parameter for forces and / or moments acting on the hollow cylinder (8) can be detected.

8. Device (1) according to one of the preceding claims, characterized in that the device (1) has a transmission device for transmitting the torque parameters detected by the torque measuring device (24) for a torque acting on the piston shaft (10) to an evaluation device.

9. Device (1) according to one of the preceding claims, characterized in that the device (1) has a storage device for storing a number of successively recorded torque parameters for a torque acting on the piston shaft (10) with the torque measuring device (24).

10. Device (1) according to one of the preceding claims, characterized in that the device (1) has a rotation device (30) with which the working tool connection device (4) is rotatable relative to the working machine connection device (3) about an axis of rotation (33), wherein the rotation device (30) has a worm gear with a driveable worm shaft (34) having an external thread (38) and with a worm wheel (31) rotatably mounted about the axis of rotation (33), which meshes with the external thread (38) of the worm shaft (34). a worm shaft (34) is rotatably mounted and axially fixed in a first bearing arrangement (36) arranged along a worm shaft axis (35) extending transversely to the axis of rotation (33) and spaced apart from the external thread (38), wherein the rotation arrangement (30) has a drive arrangement (39) which is operatively connected to a drive section of the worm shaft (34) and with which the worm shaft (34) can be driven to a rotational movement about the worm shaft axis (35), characterized in that a force measuring device (43) for detecting force parameters for axial forces exerted on the measuring section (40) of the worm shaft (34) and directed in an axial direction along the worm shaft axis (35) is located in a measuring section (40) of the worm shaft (34) between the first bearing arrangement (36) and the external thread (38). is arranged in the worm shaft (34).

11. Device (1) according to claim 10, characterized in that the worm shaft (34) has a measuring recess (41) extending along the worm shaft axis (35) in the direction of the external thread (38) on an end face (42) of the worm shaft (34) facing away from the external thread (38), in which the force measuring device (43) is arranged and fixed in such a way that tensile and / or compressive forces exerted on the worm shaft (34) can be detected by the force measuring device (43).

12. Device (1) according to claim 10 or claim 11, characterized in that the worm shaft (34) is mounted on one of the first bearing devices (36) opposite each other side of the external thread (38) in a second The storage device (37) is rotatably mounted.

13. Device (1) according to one of the preceding claims 10 to 12, characterized in that the force measuring device (43) has a sensor device and a power supply device that supplies the sensor device with electrical energy.

14. Device (1) according to claim 11 and claim 13, characterized in that the power supply device has a power transmission device with which electrical energy can be wirelessly transmitted from a power supply device to the measuring recess (41) of the worm shaft (34) rotatably mounted in the first bearing device (36).

15. Method (1) for monitoring a mechanical load on a device (1) for connecting a working tool to a working machine according to one of claims 1 to 14, characterized in that a torque parameter detected by the torque measuring device (24) for a torque acting on the piston shaft (10) is transmitted to an evaluation device and checked with the evaluation device whether the torque parameter is smaller or larger than a predefinable torque parameter threshold value.

16. Method (1) according to claim 15, characterized in that a number of the torque parameters successively recorded with the torque measuring device (24) for a torque acting on the piston shaft (10) are sent to a The data is transmitted to the storage device and stored there.

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