Boom-mounted work device, self-propelled work machine with such a boom-mounted work device, and a method for detecting the loads acting on the boom.

Abstract

Boom work device (1) for attachment to a carrier vehicle (7), with - at least one boom arm (3, 4) whose rear end (3b, 4b) can be attached to the carrier vehicle (7), - an arm end (18a) as the front end (3a, 4a) of the outrigger arm (3, 4), - a working head (2) which is attached to the arm end (18a) with its head end (18b) facing the arm end (18a), - a load measuring unit (50) with at least one load sensor (51) for detecting the loads acting on the boom arm (3, 4), wherein the load measuring unit (50) - either on or in the boom arm (3, 4) - or is arranged between the head end (18b) and the arm end (18a), characterized in that - the head end (18b) is attached to the arm end (18a) by means of a removable connecting element (58) located between the arm end (18a) and the head end (18b), - the arm end (18a) has a bearing block (54, 56) with a through opening (54a, 56a) on the surface directed towards the head end (18b), - the head end (18b) has a bearing block (55) with a through opening (55a) on the surface facing the arm end (18a), - a removable load measuring bolt (53) extends through the aligned through-openings (54a, 55a, 56a), which simultaneously serves as a connecting element (58) and load measuring unit (50).

Description

I. Area of ​​application

[0001] The invention revolves around detecting the loads acting on the boom of a boom-type implement. II. Technical background

[0002] With such a boom work device, loads are often transferred from the working head to the boom during operation, not only due to the weight of the working head, especially during dynamic operation, but often because the working head is in contact with the environment during operation and thus, for example, resistance forces are transferred from the environment to the working head and from there to the boom.

[0003] A typical example is a boom mower used to mow vegetation along the verge of a road. The working head is a mowing head, usually resting on the ground with one or more contact rollers and propelled by the forward movement of the carrier vehicle.

[0004] Depending on the contact force on the ground, the contour of the ground in the direction of travel, the type and amount of vegetation and other factors, this results in very different loads on the boom arm.

[0005] By knowing these loads, not only the position of the mowing head can be changed, for example with regard to the height or inclination of the mowing head relative to the ground, but also the adjusting elements which adjust the relative position of the usually several arm sections of the boom arm to each other, and also other parameters such as the speed of the blade shaft of the mowing head.

[0006] Similar tasks also arise with other work equipment such as a washing head with rotating brushes as a working head for cleaning the surfaces of soundproof walls or tunnels.

[0007] Often a different working head is attached to the boom for different tasks.

[0008] It is known to place sensors for measuring the load directly on the working head.

[0009] The disadvantage is that a sensor equipment is required on each individual working head used and additionally a data connection from the working head to the boom, unless the data connection from the working head to the control of the boom working device is wireless, which, however, is often prone to failure in practice.

[0010] The advantage of this method is that it measures the loads very close to where they occur, namely between the ground and the working head.

[0011] The document DE 299 07 728 U1, which represents the closest prior art, discloses a boom-type working device having the features of the preamble of claim 1.

[0012] Furthermore, reference is made to the documents GB 2 495 497 A, WO 2017 / 107 050 A1, WO 2016 / 150 514 A1, US 6 234 508 B1, EP 0 682 856 A2 and DE 102 27 261 A1. III. Description of the inventiona) Technical problem

[0013] It is therefore the object of the invention to create a boom working device which, despite a simple and only one-time structure of the sensors, reliably measures the loads at least on the boom arm, as well as a self-propelled working device equipped in this sense with such a boom working device.

[0014] The object is further to propose a method for detecting the loads acting on the boom of a boom-type implement. b) Solution to the task

[0015] This object is achieved by the features of claims 1, 17 and 18. Advantageous embodiments emerge from the subclaims.

[0016] With regard to the boom work device, this first of all includes the boom arm itself, which usually consists of several articulated arm sections and whose rear end is designed to be attached to a carrier vehicle.

[0017] In addition, the boom arm has an arm end at its front end which can be pivoted relative to the rest of the boom arm by means of a Z-joint about an axis referred to as the Z-axis, and to which the working head can be attached by means of its head end facing the boom arm, by screwing or locking.

[0018] Additionally, an X-joint can be provided in the front end area of ​​the boom arm, by means of which two arm sections can be pivoted relative to each other about an X-axis running transversely, in particular perpendicularly, to the Z-axis. The X-joint can be arranged in front of or behind the Z-joint—in the direction of the boom arm.

[0019] In such a boom work device, there is one, in particular only one, load measuring unit with at least one load sensor for detecting the loads acting on the boom.

[0020] According to the invention, this load measuring unit - either on or in the boom arm (3, 4), in particular stationary, - or arranged between the head end of the working head and the arm end of the boom arm.

[0021] This has the advantage that the required sensor equipment only needs to be present once on the boom work tool, in particular on the boom arm, and thus away from the damage-intensive working head.

[0022] Although it can only measure the loads acting on the boom, it can provide meaningful conclusions about the extent of the loads acting on the working head from the environment.

[0023] Since the load should not only be measured in one but in several different directions, the load measuring unit either contains several sensors that each measure the load in only one direction or at least one load sensor that can measure the load in several directions, for example the X and Y directions perpendicular to the Z direction.

[0024] Preferably, one wants to know all the loads acting on the cantilever arm at its front end, and therefore the load measuring unit, in particular the one or more load sensors, should measure both the forces in the X, Y and Z directions and the torsional load, i.e. moments, about these three spatial directions.

[0025] If the head end of the working head facing the boom arm is - as is usually the case - non-rotatably attached to the arm end of the boom, the measuring directions of the one or more load sensors always remain the same in their orientation to the working head, so that conclusions can be drawn about the type and direction of the forces and loads acting on the working head.

[0026] Since different working heads can be attached to the boom, which behave very differently with regard to loads, it is important that the control system controlling the boom work device also knows the relevant parameters of the working head, i.e. at least knows which type of working head is currently attached to the boom, and in particular which specific working head it is.

[0027] Even two mowing heads of the same design can impose different loads on the boom due to different manufacturing tolerances or different levels of wear when mowing the same vegetation.

[0028] For this reason, at least one detection sensor is provided to detect the working head attached to the boom arm, again - either on or in the boom arm, especially stationary, - or between the head end and the arm end.

[0029] Preferably, a detection sensor is then present in the effective range of this detection sensor on the working head, in particular on or in its head end, which the detection sensor can analyze and which contains the desired information regarding the attached working head.

[0030] Then, when attaching a working head, there is no longer any need to manually enter such working head-dependent parameters into the control system, which speeds up the work and avoids input errors.

[0031] Preferably, one of the load sensors is functionally combined with such a detection sensor, thereby reducing the number of necessary sensors and thus also the risk of damage.

[0032] If the load measuring unit is located on or in the boom arm, it is preferred - arranged either in or on the arm end of the boom arm, preferably pivotable around the Z-joint - or on or in the rest of the boom arm, i.e. on the side of the Z-joint facing away from the working head, i.e. behind the Z-joint.

[0033] The first option has the advantage that the orientation of the load measuring unit relative to the working head always remains the same, regardless of the pivot position of the Z-joint and thus of the front arm end, which greatly facilitates the evaluation and analysis of the measured loads with regard to their direction of action on the working head.

[0034] The second option, behind the Z-joint, includes several possibilities if an X-joint is also present: - either between X-joint and Z-joint - or behind both joints, regardless of the order in which they are present along the boom arm, - or in the X-joint, e.g. on or as its joint axis.

[0035] Individual load sensors or even entire load measuring units can also be present at different locations, in particular spaced along the boom arm, which then preferably measure forces or moments in different spatial directions.

[0036] The load measuring unit can also be arranged between the boom arm and the working head.

[0037] This can be useful if the working head is positively attached to the boom arm by means of a removable connecting element, for example a retractable connecting bolt, because then this remote connecting element can carry the load measuring unit or be a load measuring unit itself.

[0038] The at least one load sensor of the load measuring unit can be a strain gauge or another electrical sensor that changes its voltage or electrical resistance when loaded.

[0039] In order to protect such strain gauges from damage, they can be arranged in recesses, in particular in the front side of the arm end facing the working head or the rear side facing away from it, and in particular can also be cast in them.

[0040] The strain gauges with different orientations can be connected to each other via an electrical bridge circuit, whereby with appropriate arrangement not only the loads can be determined linearly in the individual spatial directions, but also torsional loads, i.e. torques, about these three spatial directions can be determined.

[0041] Since both strain gauges and related external circuits, especially bridge circuits, are known and can be purchased inexpensively, this results in a cost-effective load measuring unit.

[0042] Instead of installing individual strain gauges, load measuring bolts can also be used for the load measuring unit. These can also be purchased on the market and measure the force applied to the load measuring bolt, preferably in at least one of the transverse directions to the main extension direction of the load measuring bolt, and in particular also output this force to the control system. Individual strain gauges can be installed on or in such a load measuring bolt as load sensors, or other types of load sensors can be used.

[0043] Even a single load measuring bolt can form such a load measuring unit.

[0044] This makes setting up the load measuring unit and, of course, changing it easier and faster.

[0045] To connect the working head and the boom arm, a locking bolt is often used that is permanently mounted on one of the two parts, usually in the boom arm. This locking bolt is inserted into a corresponding recess in the other part to couple the two parts and in this position the two parts are locked against each other, for example by means of a movable locking element such as a pivot lever, which can preferably be operated from the boom arm.

[0046] This locking bolt can then be designed directly as a load measuring bolt, for example by permanently mounting a purchased load measuring bolt to the components that support it.

[0047] With this solution, the total number of components of the boom work device is not increased by the load measuring unit, and the boom arm-side connection from the load measuring pin to the control unit does not need to be rebuilt when changing the working head.

[0048] According to the invention, for the use of the working head and the boom arm, a removable connecting element such as a connecting bolt is used which connects the two parts in a form-fitting manner and is inserted through mutually aligned through openings of bearing blocks which are fastened to the working head on the one hand and the boom arm on the other hand.

[0049] Therefore, according to the invention, a load measuring bolt is again used as such a connecting bolt without increasing the total number of components.

[0050] By arranging preferably several pairs of through-holes and load measuring pins inserted through them, the working head can be arranged in a rotationally fixed manner at the end of the arm, and further mechanical fastening means can be dispensed with.

[0051] Since load measuring pins - especially the cost-effective ones - only measure loads in one transverse direction to their longitudinal direction, at least two load measuring pins and thus pairs of through holes are arranged in two different transverse directions of the XY plane perpendicular to the Z direction, preferably even two load measuring pins redundantly in each of these transverse directions.

[0052] Depending on their design, load measuring bolts can also measure the tensile forces prevailing in their main direction of extension. For this purpose, the load measuring bolt must of course be installed in such a way that it has corresponding stops at both ends in order to load it in the longitudinal direction, for example by designing the load measuring bolt as a screw with a screwable nut.

[0053] Another possibility is to use a so-called ring force transducer, which is available on the market, for force measurement and / or torque measurement within the measuring device.

[0054] This is a - usually cylindrical - component, to whose opposite end faces the components can be fastened, usually screwed, so that the ring force transducer measures the forces - in the axial direction and / or at least one of the transverse directions thereto - that prevail at this connection point between the two components to be connected.

[0055] The two end faces of the ring force transducer are usually designed as rings or plates that are connected to each other by webs or other connecting elements, on or in which the corresponding forces are measured, so that torques can also be determined about at least one of the radial directions of the ring force transducer, if necessary instead or additionally also about the axial direction of the ring force transducer.

[0056] Such a ring force transducer is preferably screwed with its axial direction aligned with the longitudinal direction of the Z-joint between the arm end of the cantilever arm and the head end of the working head.

[0057] With regard to a self-propelled work machine which is equipped with a previously described boom work device and wherein the load measuring unit is arranged and / or designed as described above, the control can thus control the self-propelled work machine on the basis of the signals of the load measuring unit, in particular the load sensors and / or the at least one detection sensor, by - controls the adjusting elements for adjusting the individual arm sections of the boom arm relative to each other and to the carrier vehicle, - in particular controls the swivel position of the arm end of the boom arm and / or - controls the working head, for example with regard to the drive speed of the driven tools present there, such as a mowing shaft, and / or - controls the driving speed of the carrier vehicle.

[0058] This avoids an arrangement of sensors on the working head itself that could be damaged, and it is not necessary for each working head to have its own sensor equipment.

[0059] With regard to the method for detecting the loads acting on the boom arm of a boom working device, in particular in a boom working device according to one of the preceding claims, the load - either on or in the boom arm - or measured between the head and arm ends.

[0060] This also achieves the advantages mentioned above. c) Examples of implementation

[0061] Embodiments of the invention are described in more detail below by way of example. They show: Fig. 1a, b: a known type of attachment of a working head to the free end of a boom arm in a boom-type work tool in two different side views, Fig. 2a, b: a carrier vehicle with two boom mowers in front view and in top view, Fig. 3: one of the two mowing heads in an enlarged individual view in front view, Fig. 4a, b: a first design of a load measuring unit on the boom arm of a boom working device in two different side views analogous to the Fig. 1a, b, Fig. 5: further designs of a load measuring unit on or in the boom arm of a boom work device in a side view analogous to Fig. 1a, Fig. 6a, b: a 1. design of a load measuring unit between boom arm and working head of a boom working device in side view and top view on Fig. 6a from above, Fig. 7a, b: a second design of a load measuring unit between the boom arm and the working head of a boom working device in the side view and in the view of the Fig. 7a from below.

[0062] The Fig. 1a, b show a common way of attaching an interchangeable working head 2 to the free end of a boom arm 4 of a boom working device: For fastening - viewed in the direction of the Fig. 1a - the working head 2 to be fastened, shown in dashed lines, is pushed from the right to the arm end 18a in such a way that the two sides - see Fig. 1b - from the arm end 18a in one side area protruding locking bolt 15 into a locking recess 26 formed by hook-shaped curved locking elements 20 which are formed on the head end 18b of the working head 2 facing the arm end 18a of the cantilever arm 4 and are positioned accordingly.

[0063] In this case, the arm end 18a and the head end 18b do not yet have to be in a position with their surfaces facing each other in alignment with each other, since the working head 2 can still be pivoted about the locking bolts 15 in this state.

[0064] Only by the screw connection 25 between the arm end 18a and the head end 18b, preferably on the other side area of ​​the arm end 18a facing away from the locking bolt 15, is the working head 2 positioned and fastened in a form-fitting and fixed position to the boom arm 4.

[0065] In the Fig. 1a, b further shows a Z-joint 12 in the end region of the boom arm 4, with which the foremost arm part 4.3 of the boom arm 4 facing the working head 2 is mounted as a joint part 12b relative to a joint part 12a which is fixedly fastened to the arm end 18a in a rotationally fixed manner about a Z-axis which corresponds to the direction of extension of this arm part 4.3 and / or usually runs perpendicular to the parting plane or contact surface between the arm end 18a and the head end 18b.

[0066] In this case, the pivoting is effected by two adjusting elements 60 in the form of hydraulic cylinders, which act at different points on the circumference of the arm part 4.3, the joint part 12.b, with one end and which are fastened to the arm end 18a, i.e. the other joint part 12a, with their other end.

[0067] The Fig. 2a, b and Fig. 3 show a typical application of such a fastening using a Fig. 2a, b in plan and front view of the mowing vehicle in the form of a carrier vehicle 7 with two mowing heads 2a, b each carried on a boom arm 3, 4 at their free, front end as working heads in operation: Each mowing head 2a or 2b is driven by a mowing head motor 22 arranged thereon.

[0068] Both boom arms 3, 4 are attached at their rear ends to a front end 8 mounted on the front of the carrier vehicle 7. The front end 8 carries a transverse offset rail 5 on its front side, along which a respective sliding shoe 23, 24 can be displaced in the transverse direction 19 and moved in a controlled manner during operation. One of the boom arms 4, 3 is attached to each sliding shoe 23, 24.

[0069] The boom arms 3, 4 each consist of several arm parts: The boom arm 4 consists, for example, of an arm part 4.1, which projects upwards from the sliding shoe 23 approximately in the direction of the vertical 11 and is rotatable about a vertical axis and from whose free end a further arm part 4.2 projects and is pivotable about a transverse axis and on this, in turn, a further arm part 4.3.

[0070] The angular position of the arm sections relative to one another is controlled by hydraulic cylinders arranged between them, whereby the respective mowing head 2a, b, which is additionally articulated around a Z-joint 12 at the front end of the boom arm 4, can be adjusted to any desired position with respect to the direction of travel 10 (X-direction), the horizontal transverse direction 19 (Y-direction) in this case, as well as the rotational position about the Z-axis. An additional X-joint, usually present in the boom arm 3, 4 near its free end, allows each mowing head 2a, b to be additionally pivoted about the direction of travel 10, the X-axis, and can thus be pivoted about all three spatial directions and positioned in all three spatial directions, as far as the dimensions of the boom arm 3, 4 permit.

[0071] How best Fig. 2a shows, the mowing heads 2a, b are controlled by the operator sitting in the driver's cab 6 of the carrier vehicle 7 in such a way that the mowing head 2a mows a verge area immediately next to the carrier vehicle 7 and is positioned in front of the front end 8 of the carrier vehicle 7, while the mowing head 2b mows the edge area adjoining it to the side, which is further outwards with respect to the carrier vehicle 7, and is positioned behind the first mowing head 2a in the direction of travel 10.

[0072] This division also allows obstacles 9 that are located in the area between the mowing widths of the two mowing heads 2a, b, such as road delineators, to be mowed on both sides.

[0073] For this purpose, a sensor rod 21 is usually provided on the front edge of the front mowing head 2a, which is pivoted towards the mowing head 2a when it hits such an obstacle 9 and thereby causes this mowing head 2a to fold in around the Z-joint arranged on the vehicle-side front side of this mowing head 2a with respect to the boom arm 3 carrying it.

[0074] In the Fig. 2a, b, a display element 13 is also shown in the driver's cab 6 in the operator's field of vision, on which the measured loads can be displayed.

[0075] The Fig. 3 shows the mowing head 2b working further outwards in an enlarged individual view including the Z-joint 12b, whereby the adjusting elements 60 required for this are not shown: This mowing head 2b has a housing 16 which is pivotably attached to the free end of the boom arm 4 in the transverse center via this Z-joint 12 about the Z-axis, which is usually a vertical axis.

[0076] Inside the downwardly open housing 16, a knife shaft 17 is mounted with each of its two ends around a knife shaft axis 17' in a front flange of the housing 16.

[0077] The Fig. 4a, b show a first design and arrangement of a load measuring unit 50 for measuring the loads of the boom arm 4 when the working head 2 is attached to the boom arm 4 according to the Fig. 1a, b, wherein the measuring unit 50 is arranged on the boom arm 4: The two locking bolts 15 - or just one - are designed as load measuring bolts 53 and measure the loads acting on these bolts.

[0078] For this purpose, strain gauges 57 are preferably arranged on or in each of the load measuring bolts 53, preferably distributed over the circumference, preferably several of them, in particular in each case in the axial length range in which the locking elements 20 rest against the locking bolt 15 designed as a load measuring bolt 53, so that each of the load measuring bolts 53 can measure loads occurring on it in the two transverse directions to its axial direction 53'.

[0079] By appropriate electronic interconnection of the signals of the strain gauges 57, not only forces in these two transverse directions can be measured, but if necessary also moments about these two transverse directions and / or about its axial direction 53'.

[0080] The Fig. 5 shows, in a side view, further positions at which a load measuring unit 50 can be arranged on or in the boom arm 4, in which in this case upstream, i.e. on the side facing away from the working head 2, of the Z-joint 12, an X-joint 27 is shown, by means of which two interconnected arm parts 4.3 and 4.4 can be pivoted relative to each other in the X-direction in the end region of the boom arm 4, and thus also of the working head 2: The load measuring unit 50 can consist of one or preferably several strain gauges 57 - then electronically interconnected via an evaluation circuit - or comprise one or more load measuring bolts 53 - regardless of the functional principle according to which they function - or be designed in any other way, in particular as shown in the structure in the Fig. 6a, b or Fig. 7a, b, but with a different positioning, and in particular any type of load sensors 51.

[0081] Possible positions for arranging such a load measuring unit 50 - individually or in total - are shown: - at or in the arm end 18a, i.e. in front of, so to speak downstream, the Z-joint 12, - on or in the remaining boom arm 4 behind, so to speak upstream of the Z-joint 12, in particular downstream and / or upstream of the X-joint 27, for example also between the Z-joint 12 and the X-joint 27.

[0082] The Fig. 6a, b and 7a, b, however, show an arrangement of the load measuring unit 50 between the boom arm 4 and the working head 2, in particular between the arm end 18a and the head end 18b: According to the Fig. 6a, b, the load measuring unit 50 in the form of a solution which is easy to handle consists in using a so-called ring force transducer 61 instead of individual load sensors and in fixing it, in particular by screwing it, between the arm end 18a and the head end 18b.

[0083] This is a component 61 - usually cylindrical and / or plate-shaped - which is available on the market and which, depending on the design, can measure forces mostly in its axial direction and / or in at least one of its two transverse directions thereto, but above all can also measure torques around its longitudinal axis 61'.

[0084] Then such a ring force transducer 61 only has to be screwed between the, for example, plate-shaped arm end 18a and the, for example, also usually plate-shaped head end 18b, and the signal line 61a leading away from the ring force transducer 61 has to be connected to the control 1* of the boom working device 1.

[0085] The Fig. 7a, b show another design of the load measuring unit 50 arranged between the boom arm 4 and working head 2, here between arm end 18a and head end 18b: The load measuring unit 50 comprises load measuring bolts 53, which are pushed through alternating through openings of bearing blocks, whereby in this case three bearing blocks 54, 55, 56 are arranged in series.

[0086] How Fig. 7a shows, the two bearing blocks 54, 56 are fastened to the arm end 18a of the cantilever arm 4 and protrude from there towards the head end 18b of the working head 2, while the bearing block 55 is conversely fastened to the head end 18b, on the side facing the arm end 18a.

[0087] The bearing block 55 projects between the two other bearing blocks 54, 56 in such a way that the through openings 54a, 55a, 56a present in each of the bearing blocks are aligned with each other, so that the load measuring bolt 53, which fits precisely there, extends through all three and thus connects the arm end 18a opposite the arm end 18b at one point.

[0088] In the axial direction, axial spacer rings 59 are arranged between the bearing blocks 54, 55, 56, which position the bearing blocks and thus the arm end 18a and head end 18b against each other in the axial direction of the load measuring bolts 53.

[0089] With only one such connection, this would still be a pivoting connection.

[0090] Therefore, as is especially the view of the Fig. 7b shows - two such load measuring bolts 53 each arranged as described between the arm end 18a and the head end 18b, wherein their longitudinal extensions 53' are not aligned with each other, but cross each other, in particular at right angles to each other.

[0091] The load measuring bolts 53 therefore also serve as positive connection elements 58 between the head end 18b and the arm end 18a. LIST OF REFERENCE SYMBOLS 1 boom work tool 1* Control 2, 2a, b Working head, mowing head 3, 4 boom arm 3a front end 3b rear end 3.1 / .2 / .3 armrest 4a front end 4b rear end 4.1 / .2 / .3 / .4 armrest 5 Transverse offset rail 6 Driver's cab 7 Carrier vehicle 8 Stem 9 Obstacle 10 Direction of travel 11 vertical 12 Z-joint 12a, 12b joint part 13 sensing roller 14 sensing roller 15 locking bolts 16 housings 17 Knife shaft 17' knife shaft axis 18a Armende 18b Head end 19 Transverse direction 20 locking element 21 Touch rod 22 Mower head motor 23 Sliding shoe 24 Sliding shoe 25 screw connection 26 Locking recess 27 X-joint 50 load measuring unit 51 Load sensor 52 detection sensor 53 load measuring bolts 53' longitudinal direction 54 bearing block 54a passage opening 55 bearing block 55a passage opening 56 bearing block 56a passage opening 57 strain gauges 58 connecting element 59 spacer ring 60 control element 61 ring force transducers 61a Signal line

Claims

[1] Boom working device (1) for attachment to a carrier vehicle (7), with - at least one boom arm (3, 4), the rear end (3b, 4b) of which can be attached to the carrier vehicle (7), - an arm end (18a) as the front end (3a, 4a) of the boom arm (3, 4), - a working head (2) which is fastened to the arm end (18a) with its head end (18b) facing the arm end (18a), - a load measuring unit (50) with at least one load sensor (51) for detecting the loads acting on the cantilever arm (3, 4), wherein the load measuring unit (50) - either on or in the boom arm (3, 4) - or is arranged between the head end (18b) and the arm end (18a), characterized by , that - the head end (18b) is attached to the arm end (18a) by means of a connecting element (58) which is removable between the arm end (18a) and the head end (18b), - the arm end (18a) has a bearing block (54, 56) with a through opening (54a, 56a) on the surface directed towards the head end (18b), - the head end (18b) has a bearing block (55) with a through opening (55a) on the surface facing the arm end (18a), - a removable load measuring bolt (53) extends through the aligned through openings (54a, 55a, 56a), which simultaneously serves as a connecting element (58) and load measuring unit (50). [2] Boom working device according to claim 1, characterized by , that - the arm end (18a) is pivotable relative to a remainder of the boom arm (3, 4), by means of a Z-joint (12) about a Z-axis (Z) and / or by means of an X-joint (27) about an X-axis (X), and / or - the boom working device (1) comprises only one load measuring unit (50). [3] Boom working device according to one of the preceding claims, characterized by , that - the load measuring unit (50) can detect forces acting on the cantilever arm (3, 4) in more than one direction, in particular in the X and Y directions, - in particular, the load measuring unit (50) can measure forces acting on the boom (3, 4) in the X, Y and Z directions and / or detect moments acting on the boom around the X, Y and Z directions, and / or - in the load measuring unit (50) there are several load sensors (51a, b), in particular measuring in different directions, for detecting the loads acting on the cantilever arm (3, 4). [4] Boom working device according to claim 2 and, if desired, according to claim 3, characterized by that the load measuring unit (50) - is arranged either at or in the arm end (18a) - or on / in the remainder of the cantilever arm (3, 4) behind the Z-joint (12), in particular between the Z-joint (12) and the X-joint (27) or behind the X-joint (27) or in the X-joint (27), in particular several load sensors (51) or load measuring units (50) at different points along the cantilever arm (3, 4) measure the forces or moments in different spatial directions. [5] Boom working device according to one of the preceding claims, characterized by , that - the boom arm (3, 4) is positively connected to the working head (2) via a removable connecting element (58), - the load measuring unit (50) is present on the connecting element (58) or is itself the connecting element (58). [6] Boom working device according to one of the preceding claims, characterized by , that - the head end (18b) is fixed to the arm end (18a) in a rotationally fixed manner, - thereby the orientation of the load measuring unit (50), in particular its sensors (51), relative to the orientation of the working head (2) is always the same regardless of the pivoting position of the arm end (18a). [7] Boom working device according to one of the preceding claims, characterized by that at least one detection sensor (52) for detecting the attached working head (2), at least with regard to its type, preferably with regard to its identity, - either on or in the boom arm (3, 4), in particular stationary, - or is arranged between the head end (18b) and the arm end (18a). [8] Boom working device according to claim 7, characterized by , that - at least one detection sensor (52) and one load sensor (51) are functionally combined, and / or - the load measuring unit (50) comprises at least one detection sensor (52). [9] Boom working device according to one of the preceding claims, characterized by , that - the load sensor (51) of the load measuring unit (50) is an electrical sensor, in particular an electrical load sensor (51) measuring a change in the electrical voltage and / or the electrical resistance, - in particular the load measuring unit (50) comprises a strain gauge (57), - the strain gauge (57) is arranged in particular in a recess in the arm end (18a) or in the remainder of the cantilever arm (3, 4) and is in particular cast therein. [10] Boom working device according to claim 9, characterized by , that - several strain gauges (57) with different orientations are present, - in particular the strain gauges (57) are connected to one another via an electrical bridge circuit, - in particular such that at least one pair of strain gauges (57) measures a bending load on the arm end (18a) and / or at least one pair of strain gauges (57) measures a torsional load on the arm end (18a), in particular about the Z-axis. [11] Boom working device according to one of the preceding claims, characterized by , that - the load measuring unit (50) comprises at least one load measuring bolt (53) which measures and in particular outputs the force applied to the load measuring bolt (53) in at least one of the transverse directions to the direction of extension (53') of the load measuring bolt (53) and / or in its direction of extension (53'). [12] Boom working device according to one of the preceding claims, wherein - the head end (18b) is attached to the arm end (18a) by means of a locking bolt (15) fixed to the arm end (18a), which can be locked relative to the head end (18b), characterized by , that - the locking bolt (15) is designed as a load measuring bolt (53). [13] Boom working device according to one of the preceding claims, characterized by , that - at least two load measuring bolts (53) are present, preferably extending in different, in particular perpendicular to each other, transverse directions (X, Y) to the Z direction. [14] Boom working device according to one of claims 11 to 13, characterized by , that - the forces acting on the load measuring pin (53) are measured in two radial planes of the load measuring pin (53) which are axially spaced apart in the direction of extension (53'), - in particular when using the load measuring bolt (53) as a connecting element (58), two bearing blocks (54, 56) with mutually aligned through openings (54a, 56a) are arranged either at the arm end (18a) or at the head end (18b), between which the bearing block (55) attached to the other part fits with its through opening (55a), - the load measuring bolt (53) extends through all three bearing blocks (54, 55, 56). [15] Boom working device according to one of the preceding claims, characterized by , that - the at least one load sensor (51) is arranged at the arm end (18a) of the cantilever arm (3, 4) without contact with the head end (18b) of the working head (2) and - measures contactless at the head end (18b). [16] Boom working device according to one of the preceding claims, characterized by , that - the load measuring unit (50) comprises a, in particular cylindrical, in particular annular, ring force transducer (61), - which is capable of measuring at least forces in its axial direction (61') and / or torques about one of the transverse directions thereto, - which is arranged in particular with its axial direction (61') extending in the longitudinal direction (10) between the arm end (18a) and the head end (18b). [17] Self-propelled work machine with - a carrier vehicle (7), - the boom working device (1) according to one of the preceding claims, comprising - the boom arm (3, 4) with adjusting elements for adjusting the arm parts (3.1, 3.2, 3.3 or 4.1, 4.2, 4.3, 4.4) relative to each other, - the working head (2) attached to the free, front (3a, 4a) end of the boom (3, 4) which, during operation, comes into contact with the environment away from the carrier vehicle (7), - the load measuring unit (50) for measuring the loads acting on the cantilever arm (3, 4), and - a control (1*) for controlling at least the control elements, characterized by , that - the control (1*) of the boom working device (1) controls the adjusting elements depending on the signals from the load measuring unit (50). [18] Method for detecting the loads acting on the boom arm (3, 4) of a boom working device (1) in a boom working device (1) according to one of claims 1 to 16, characterized by that the load - either on or in the boom arm (3, 4), - or between the head end (18b) of the working head (2) and the arm end (18a) of the boom arm (3, 4).

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