Construction machine, system and construction kit

Abstract

The invention relates to a construction machine (10) in the form of an excavator, having: an upper part (12) which is rotatable about a vertical axis on an undercarriage (11); an adjustable boom (15) on the upper part (12) for the purposes of holding and moving a tool (17); a dozer blade (14) which is height-adjustable relative to the undercarriage (11) but is not adjustable in terms of transverse inclination; and a means for automatic height control of the dozer blade (14). The invention also relates to a system for automatic height control of a dozer blade, and to a construction kit for retrofitting a construction machine.

Description

[0001] Construction machinery, system and kit

[0002] Description

[0003] The invention relates to a construction machine as an excavator, a system for height control and a kit.

[0004] An excavator is a construction machine with an undercarriage and an upper carriage (the latter also referred to as the upper section), whereby the upper carriage can be rotated relative to the undercarriage about a vertical axis, in particular endlessly, and a tool is held on an adjustable boom, such as an excavator bucket, a leveling beam or a milling machine.

[0005] Part of the undercarriage is a wheeled or tracked chassis (the latter also known as a crawler chassis). A tracked chassis is preferred. A height-adjustable dozer blade is mounted on the undercarriage (see, for example, DE 3838006 C2). The effective width of the dozer blade on an excavator typically extends across the track width of the undercarriage.

[0006] Typically, a hydraulically height-adjustable dozer blade is mounted on the undercarriage. Systems for adjusting the height of dozer blades are generally known. Such systems have so far been reserved for special construction machines (e.g., dozers, graders), which have dozer blades that, in addition to the simple lifting function for height adjustment, are also equipped with additional functions, such as a rolling function to compensate for slopes across the roadway. Rolling refers to the movement of the dozer blade around a longitudinal axis of the construction machine and is also referred to as transverse tilt.

[0007] On the one hand, these special construction machines can only be operated by experienced drivers due to their diverse dozer blade functions. On the other hand, their use only becomes worthwhile when the area to be leveled is of a certain size, as these construction machines cannot normally be used for any other work on the construction site.

[0008] The object of the invention is to create a construction machine as an excavator with improved leveling function.

[0009] To achieve the object, the construction machine according to the invention has the features of claim 1. In particular, the construction machine is provided as an excavator with an upper part rotatable about a vertical axis on an undercarriage and an adjustable boom on the upper part for receiving and moving a tool, as well as with a dozer blade that is height-adjustable relative to the undercarriage but not adjustable in its transverse inclination, and with an automatic height control of the dozer blade.

[0010] The construction machine chosen was an excavator, which is used on most construction sites anyway and is typically equipped with a tracked chassis (crawler chassis). Alternatively, a wheeled chassis can be provided. A combination of both is also possible. The excavator also makes automated leveling of smaller areas such as parking lots, short stretches of road, building foundations, or lawns cost-effective.

[0011] The excavator deliberately does not have a dozer blade with a roller function (cross slope), preferring to only control the existing lifting function of the dozer blade. An accidental inclination transverse to the direction of travel is accepted here, as the inclination can also be eliminated through a suitable working method, which has not been used to date. The suitable working method, for example, consists in first leveling a strip along the edge of a rectangular, flat area using automatic height control. Then, transversely to this and starting at the edge whose height is now correct in the longitudinal direction, the remaining area is gradually leveled strip by strip with automatic height control. The deliberate restriction to the lifting function also makes the construction machine easy to operate. The excavator driver does not have to learn any additional functions.The automatic height control can be activated at the push of a button and then keeps the dozer blade at a preset height, allowing the excavator operator to concentrate on moving the machine forward. Retrofitting is also easy. The dozer blade is preferably designed and positioned to be height-adjustable only. This means that other movements, such as tilting the dozer blade forward or backward, are not possible.

[0012] The upper section of the excavator is, in particular, continuously rotatable. The undercarriage is mounted on the undercarriage. A hydraulic pump is preferably positioned on the upper section to generate hydraulic working pressure. Hydraulic lines lead from the upper section to the undercarriage via a rotary union. The tool on the boom of the upper section is preferably a bucket, a dozer, a grapple, a milling machine, or another suitable tool.

[0013] Optionally and according to the invention (claim 2), the automatic height control regulates the height of the dozer blade relative to the height of a reference external to the construction machine. The reference can be, for example, a fixed point or a fixed plane external to the construction machine. A reference plane is generated, for example, by a laser beam rotating around a stationary axis, which can be scanned by a laser receiver.

[0014] Optionally and according to the invention (claim 3), the automatic height control includes a receiver for height determination signals, in particular a receiver on the dozer blade. By preferably having only one receiver on the dozer blade, the position or height of the dozer blade can be automatically incorporated into the control loop.

[0015] Optionally and according to the invention (claim 4), the receiver is at least

[0016] - a camera,

[0017] - a tactile organ,

[0018] - a laser receiver,

[0019] - an ultrasound receiver,

[0020] - an infrared receiver,

[0021] - a radio receiver, or

[0022] - a receiver for electromagnetic waves.

[0023] Any signals for height determination or a reference external to the construction machine are adapted to the selected receiver. Optionally, and according to the invention (claim 5), the receiver is battery-operated. This also facilitates the retrofitting of automatic height control.

[0024] Optionally and according to the invention (claim 6), the automatic height control includes an actuator for adjusting the height of the dozer blade depending on the signals received from the receiver. For example, at least one hydraulic cylinder controlled by hydraulic working pressure is provided as the actuator. The dozer blade is then hydraulically height-adjustable, with the automatic height control including one or more hydraulic valves controlled depending on the signals received from the receiver. For example, these are electro-hydraulic valves controlled by an electronic control system depending on the received signals. The process runs automatically and without operator intervention.

[0025] The dozer blade is preferably (claim 7) height-adjustable on the undercarriage, i.e., not on the upper part. In particular, the dozer blade is only height-adjustable.

[0026] Optionally and according to the invention (claim 8), the automatic height control includes an electronic control system located outside the dozer blade on the construction machine, in particular on a rotatable upper part of the construction machine. The electronic control system is preferably wirelessly connected to the receiver for signals for height determination. A wireless connection between the control system and the receiver is particularly advantageous for a continuously rotatable upper part of the construction machine.

[0027] To keep soil in front of the dozer blade when in use, it can be equipped with side plates on both sides. The side plates can be removable.

[0028] Optionally, and according to the invention (claim 9), a first free end of at least one of the side plates is directed outward relative to the side plate, preferably at an angle. The outwardly directed free end increases the effective pushing width of the dozer blade with side plates. The angled orientation acts as a guide for the removed subsoil. A wider dozer blade can be avoided in order not to increase the overall width of the excavator and thus complicate its transport on a low-loader.

[0029] In particular, the blade body of the dozer blade has a rear side facing the construction machine and a front side opposite thereto, wherein the side plate can be attached to the blade body such that the first free end of the side plate protrudes beyond the front side. The front side of the blade body faces in the direction of travel during dozing. Preferably, two correspondingly designed side plates are arranged on the dozer blade.

[0030] Furthermore, in particular, the side plate can be attached to the blade body in such a way that a second free end of the side plate protrudes beyond the rear of the blade body. The rear of the blade body faces the construction machine. The second end protruding at the rear can at least partially shield the gap between the dozer blade and the construction machine.

[0031] Also, in particular, the side plate has a connecting element for at least indirectly connecting the side plate to the shield body. Preferably, the connecting element is detachably and, in particular, captively held on the side plate.

[0032] Also in particular, the dozer blade has a blade body and at least one side plate according to the invention, preferably two side plates.

[0033] Also in particular, the side plate is held on a fastening device connected to the shield body.

[0034] Also, in particular, a front side of the shield body is concavely curved. A corresponding curvature axis runs transversely to the direction of travel and in the longitudinal direction of the shield body.

[0035] The invention also relates to a system for automatically controlling the height of a dozer blade of a construction machine according to one of claims 1-9. The system has the following features: a) the dozer blade is height-adjustable using a hydraulic working pressure, b) a receiver on the construction machine receives signals for determining the height, in particular a laser receiver, c) the receiver sends height signals corresponding to the signals for determining the height to an electronic control system, d) the electronic control system determines electrical signals from the height signals and sends them to an electro-hydraulic valve device on the construction machine, e) the electro-hydraulic valve device receives the electrical signals and converts them into a control of a hydraulic volume flow, f) the hydraulic volume flow flows into a hydraulic working circuit for adjusting the height of the dozer blade or into a hydraulic pilot control circuit for the working circuit.

[0036] The signals for determining the height are transmitted, in particular, from a stationary transmitter outside the construction machine. However, it can also be a mobile transmitter, especially if its position over time is known. Preferably, only one receiver is provided.

[0037] Optionally and according to the invention (claim 11), the system has the following features: a) the electronic control is arranged on the upper part, b) the electro-hydraulic valve device is arranged on the upper part.

[0038] Optionally and according to the invention (claim 12), preferably only one receiver for signals for determining height is arranged on the dozer blade.

[0039] Optionally, and according to the invention (claim 13), the receiver is mounted on a mast on the dozer blade, wherein the mast is, in particular, bendable and / or elastically flexible. If the construction machine is designed as an excavator with a boom mounted on the upper section, the boom or a tool attached thereto may collide with the receiver or mast. The design according to the invention can limit the potential damage.

[0040] Advantageously (claim 14), a kit for retrofitting a construction machine, namely an excavator with an upper part rotatable about a vertical axis on an undercarriage and an adjustable boom on the upper part for receiving and moving a tool and with a dozer blade adjustable in height relative to the undercarriage but not adjustable in transverse inclination, consists of at least

[0041] - a receiver for signals for determining height, preferably a laser receiver, in particular with a mast,

[0042] - a transmitting unit, in particular on the receiver, for the preferably wireless transmission of signals to an electronic control system,

[0043] - the electronic control, with a receiving unit for the signals from the transmitting unit and for controlling an electro-hydraulic valve device.

[0044] According to the invention (claim 15), the kit can comprise the electro-hydraulic valve device for receiving signals from the electronic control and for controlling a hydraulic volume flow for an indirect or direct height adjustment of the dozer blade.

[0045] Also according to the invention (claim 16), the kit may comprise hydraulic hoses and couplings for connecting the electro-hydraulic valve device to a hydraulic working circuit or pilot control circuit in the construction machine.

[0046] Further features of the invention will become apparent from the description and the claims. Advantageous embodiments of the invention are explained in more detail below with reference to the drawings. They show:

[0047] Fig. 1 a construction machine as state of the art, namely an excavator in a highly simplified side view,

[0048] Fig. 2 a dozer blade in perspective view,

[0049] Fig. 3 the dozer blade in a top view,

[0050] Fig. 4 the dozer blade in a front view,

[0051] Fig. 5 a detail of the dozer blade, namely a side plate, in perspective view,

[0052] Fig. 6 the side plate connected to the dozer blade in another perspective view,

[0053] Fig. 7 the side plate according to Fig. 6, with a released connecting element,

[0054] Fig. 8 the side plate according to Fig. 7, completely detached from the dozer blade,

[0055] Fig. 9 the dozer blade in front view, i.e. with a view of the side plate, Fig. 10 a view as in Fig. 9, but showing some hidden edges,

[0056] Fig. 11 the excavator with height control system with pilot control,

[0057] Fig. 12 the excavator with height control system without pilot control,

[0058] Fig. 13 the excavator with height control system with electronic control,

[0059] Fig. 14 the height control system with pilot control,

[0060] Fig. 15 Illustration for the definition of rotary movements of the dozer blade in space.

[0061] Fig. 1 shows a simplified representation of a construction machine 10 as prior art, namely an excavator, with an undercarriage 11 and an upper section 12 that can rotate continuously thereon. The undercarriage 11 is equipped with a crawler track 13 and has a height-adjustable dozer blade 14 on the front. The upper section 12 is provided with a multiply adjustable boom 15, at the free end 16 of which a tool 17 is held, which is shown here as a shovel.

[0062] Reference is made to Fig. 15:

[0063] Using suitable adjustment devices, the dozer blade 15 can be rotated about a longitudinal axis X (roll / tilt), a transverse axis Y (tilt), and a vertical axis Z (yaw). The longitudinal axis X is also the longitudinal axis of the construction machine 10. The transverse axis Y and the vertical axis Z run through the dozer blade 14 or at a short distance from it. In fact, excavators often have a dozer blade that is often only height-adjustable, namely, it can be raised and lowered, and pivots about a transverse axis H. The transverse axis H runs horizontally and transversely to the longitudinal axis X through the undercarriage 11.

[0064] The dozer blade 14 and its individual components are shown in Figs. 2 to 10. The dozer blade 14 comprises a blade body 18, side walls 19, 20, side plates 21, 22, fastening devices 23, 24, and connecting elements 25, 26 (fourfold). The connecting elements here are bolts 25 and nuts 26.

[0065] The shield body 18 has a front shield plate 27 and a rear reinforcement profile 28, see in particular Fig. 10. The shield plate 27 is concavely curved at the front with a lower edge 29 for pushing off soil or for supporting on a surface. The side plates 21, 22 each extend with a lower edge 30 to the lower edge 29 and with an upper edge 31 approximately to a highest edge 32 of the shield plate 27. Furthermore, the side plates 21, 22 are each provided with a first free end 33 and a second free end 34. The first free end 33 projects beyond the shield plate 27 at the front. Correspondingly, the second free end 34 projects beyond the shield plate 27 at the rear, also beyond the reinforcement profile 28. At the same time, the side plates 21, 22 are divided into a longitudinal area 35 and an area 36 angled thereto, with an upright bend line 37 in between.The bending line 37 is located a short distance in front of the shield plate 27, so that the first free end 33 approximately coincides with the angled region 36. The longitudinal region 35 extends transversely to the shield plate 27 from the bending line 37 over the edge contour of the shield plate 27 and the reinforcement profile 28 and then merges into the second free end 34. Furthermore, the longitudinal region 35 partially abuts the adjacent side wall 19, 20.

[0066] As can be seen in Figs. 2 to 8, the angled area 36 is angled outwards in each case, so that the contour of the dozer blade 14 which is effective when pushing away soil is wider than in the case of a dozer blade without angled side plates 20, 21.

[0067] The side plates 21, 22 are detachably fastened to the shield body 18 by means of fastening devices 23, 24. For this purpose, the fastening devices 23, 24 are provided at the rear with a convexly curved contour 38, corresponding to the concave curvature of the shield plate 27, see in particular Fig. 6. Preferably, the fastening devices 23, 24 are welded onto the shield plate 27, i.e., permanently connected to it. In contrast, there is a detachable connection between the fastening devices 23, 24 and the respective side plates 21, 22. The detachable connection is made possible here by the aforementioned connecting elements 25, 26 and a suitable shape and contour of the fastening devices 23, 24.

[0068] The nuts 26, as connecting elements, in particular fastening elements, are rotatably and simultaneously captively mounted on the outside of the side plates 21, 22. For this purpose, the nuts 26 have a circumferential collar at their ends (not visible in Fig. 5), which is rotatably held behind washers 39 with some play. The washers 39 are arranged via openings (not shown) in the longitudinal regions 35 and are screwed there, see in particular Figs. 5 and 9.

[0069] The fastening devices 23 each have two slots 40, 41, which are open on three sides, namely in the direction of the side plates 21, 22, i.e., on an outer side 23a, in the direction of the other fastening device, i.e., on an inner side 23b, and opposite the convex contour 38, i.e., toward a free end face 42. On the inside, the slots 40, 41 are provided with a slot extension 43 that is only effective at the end and appears as a recess in the inner side 23b in a plan view of the inner side 23b. End-side here means opposite the free end face 42, i.e. at a closed end of the respective slot 40, 41. The slot extension 43 can, for example, be formed by a countersunk hole with a larger diameter than the width W of the respective slot 40, 41 and thus forms a circumferential shoulder 44. The direction of the width W can be seen in Fig. 8, 10, as can the slot longitudinal direction L.

[0070] The bolts 25 provided as connecting elements each have a bolt head 45, which fits into the slot extension 43 in the longitudinal direction of the bolt 25 and is prevented from exiting the respective slot 40, 41 in the slot longitudinal direction L by the shoulder 44. In this respect, the arrangement and contour of the bolt head 45 and the slot extension 43 counteract the respective bolt 25 from being pushed out of the slot 40, 41. At the same time, the arrangement and contour of the bolt head 45 and the slot extension 43 can be designed such that the bolt head 45 is held in a torsion-proof manner.

[0071] When assembling the side plates 21, 22, the bolts 25 are initially only loosely connected to the nuts 26 so that the bolt head 45 is at a significant distance from the inner side 46 of the longitudinal region 35, see Fig. 7, lower bolt 25. This allows the bolts 25 to be inserted into the slots 40, 41 in the slot longitudinal direction L. The bolt heads 45 are aligned so that they can enter the slot extensions 43. The bolts 25 are then tightened by turning the nuts 26 so that the bolt heads 45 enter the slot extensions 43. This tightened position is shown in Fig. 7 for the upper bolt 25. The side plates 21, 22 are thus firmly connected to the rest of the dozer blade. A system for automatically adjusting the height of the dozer blade 14 is schematically shown in Figs. 11 to 14. Fig. 11, 13 and 14 refer to a system with pilot control and Fig. 12 to a system without pilot control.

[0072] As can be seen in Fig. 11, a receiver for signals for determining height, in particular a laser receiver 51, is held on a mast 50 on the dozer blade 14 of the construction machine 10. An external reference transmitter R generates a signal for the laser receiver 51, namely a reference plane 52 generated by a rotating laser beam. The laser receiver 51 detects the reference plane 52. This is a common technique.

[0073] The mast 50 is bendable or elastically flexible so that any possible and / or accidental contact of the boom 15 or the tool 17 with the laser receiver 51 causes no or minimal damage.

[0074] The laser receiver 51 includes a transmitter unit 53, which wirelessly transmits signals S, preferably via radio, in particular via Bluetooth, to a receiver unit 54 of an electronic control unit 55. While the laser receiver and transmitter unit are mounted on the undercarriage 11 by means of the dozer blade 14, the receiver unit 54 and electronic control unit 55 are located in the upper section 12. Continuous rotation of the upper section 12 relative to the undercarriage 11 is unproblematic due to the wireless transmission of the signals S.

[0075] The height adjustment of the dozer blade 14 is achieved by a hydraulic cylinder 56, which can be actuated from both sides and is part of a hydraulic working circuit 57. The hydraulic cylinder 56 actively moves the dozer blade 14 up and down.

[0076] A manual control unit 58 is provided in the upper section 12 and can be operated by an operator (not shown). The control unit 58 controls a valve 60 via a hydraulic pilot control circuit 59, with which the supply of working pressure in the working circuit 57 to the hydraulic cylinder 56 can be controlled. This type of hydraulic pilot control is conventional and well-known. For the sake of simplicity, the hydraulic pump with supply and return lines are not shown in Figs. 11 to 14. The system for automatic height control is partially integrated into the already existing manual control of the hydraulic cylinder 56. For this purpose, the electronic control unit 55 is connected to an electro-hydraulic valve device 61, which is hydraulically connected to the pilot control circuit 59, parallel to the manual control unit 58. The electronic control unit 55 determines electrical signals corresponding to hydraulic pressures from the signals received from the receiving unit 54.The electrohydraulic valve device 61 receives the electrical signals from the controller 55 and converts the signals into a hydraulic flow control. The hydraulic flow flows into the pilot circuit 59 to actuate the valve 60 (see also Fig. 14).

[0077] In the embodiment shown in Fig. 12, the system is shown without pilot control. The hydraulic pilot control circuit 59 and the valve 60 are not provided. Rather, the manual control unit 58 and the electro-hydraulic valve device 61 directly influence the hydraulic working circuit 57. In Fig. 14, this system without pilot control would not have the valve 60 or the pilot control circuit 59. Instead, the control unit 58 would be connected directly to the working circuit 57.

[0078] In the embodiment shown in Fig. 13, the system is shown with electronic control. The control unit 58 is connected to the electrohydraulic valve device 61 via a bus system 62, preferably a CAN bus, as is the electronic control unit 55 with the receiving unit 54.

[0079] *****

[0080] List of reference symbols

[0081] 10 Construction machine (excavator) 36 angled area (the

[0082] 11 Undercarriage side plate)

[0083] 12 Upper part 37 Crease line (in the side plate)

[0084] 13 Tracked chassis 38 convex contour (the

[0085] 14 Dozer blade mounting device)

[0086] 15 booms 39 discs

[0087] 16 free end 40 slot

[0088] 17 tool 41 slot

[0089] 18 Shield body 42 free front side (the

[0090] 19 Side wall fastening device)

[0091] 20 Side wall 43 Slot extension (recess)

[0092] 21 Side plate 44 Paragraph (through the

[0093] 22 Side plate slot extension)

[0094] 23 Fastening device 45 Bolt head

[0095] 23a Outside 46 Inside of the side plate

[0096] 23b Inside page 47

[0097] 24 Fastening device 48

[0098] 25 Connecting elements (bolts) 49

[0099] 26 connecting elements (nuts) 50 mast

[0100] 27 Shield plate 51 Laser receiver

[0101] 28 Reinforcement profile 52 Reference plane

[0102] 29 Lower edge 53 Transmitter unit

[0103] 30 Bottom edge 54 Receiver unit

[0104] 31 top edge 55 electronic control

[0105] 32 highest edge (of the shield plate) 56 hydraulic cylinders

[0106] 33 first free end (of the 57 hydraulic working circuit side plate) 58 manual control unit

[0107] 34 second free end (of the 59 hydraulic pilot circuit side plate) 60 valve

[0108] 35 longitudinal area (the 61 electro-hydraulic valve device side plate) 62 Bus system H swivel axis for

[0109] Height adjustment

[0110] L slot longitudinal direction

[0111] R external reference provider

[0112] S wireless signals

[0113] W Direction of the width of the slot

[0114] X Longitudinal axis

[0115] Y transverse axis

[0116] Z vertical axis

Claims

Patent claims 1. Construction machine (10) as an excavator, with an upper part (12) which can be rotated about a vertical axis on an undercarriage (11) and an adjustable boom (15) on the upper part (12) for receiving and moving a tool (17), with a dozer blade (14) which is height-adjustable relative to the undercarriage (11) but not adjustable in its transverse inclination, and with an automatic height control of the dozer blade (14).

2. Construction machine (10) according to claim 1, characterized in that the automatic height control regulates the height of the dozer blade (14) relative to the height of a reference (52) outside the construction machine (10).

3. Construction machine (10) according to claim 1, characterized in that the automatic height control includes a receiver (51) for signals for determining the height, in particular a receiver (51) on the dozer blade (14).

4. Construction machine (10) according to claim 3, characterized in that the receiver (51) at least - a camera, - a tactile organ, - a laser receiver (51), - an ultrasound receiver, - an infrared receiver, - a radio receiver, or - is a receiver for electromagnetic waves.

5. Construction machine according to claim 4, characterized in that the receiver (51) is battery-operated.

6. Construction machine (10) according to claim 4, characterized in that the automatic height control includes an actuator (56) for adjusting the height of the dozer blade (14) in dependence on the signals received by the receiver (51), wherein the dozer blade (14) is hydraulically height-adjustable and the automatic height control includes one or more hydraulic valves (61) which are controlled in dependence on the signals received by the receiver (51).

7. Construction machine (10) according to claim 1, characterized in that the Dozer blade (14) is held on the undercarriage (11) in a height-adjustable manner.

8. Construction machine (10) according to claim 1, characterized in that the automatic height control includes an electronic control (55) which is provided outside the dozer blade (14) on the construction machine (10), in particular on the rotatable upper part (12) of the construction machine (10), and which is preferably connected wirelessly to the receiver (51).

9. Construction machine (10) according to claim 1, characterized by at least one side plate (21, 22) laterally on a blade body (18) of the dozer blade (14), wherein a first free, front end (33) of the side plate (21, 22) is directed outwards relative to the side plate, in particular obliquely outwards.

10. A system for automatically controlling the height of a dozer blade (14) of a construction machine (10) according to any one of claims 1-9, having the following features: a) the dozer blade (14) is height-adjustable using a hydraulic working pressure, b) a receiver (51) on the construction machine (10) receives signals for determining the height, in particular a laser receiver (51), c) the receiver (51) sends height signals corresponding to the signals for determining the height to an electronic controller (55), d) the electronic controller (55) determines electrical signals from the height signals and sends them to an electro-hydraulic valve device (61) on the construction machine (10), e) the electro-hydraulic valve device (61) receives the electrical signals and converts them into a control of a hydraulic volume flow,f) the hydraulic volume flow flows into a hydraulic working circuit (57) for the height adjustment of the dozer blade (14) or into a hydraulic pilot control circuit (59) for the working circuit (57).

11. System according to claim 10, characterized by the following features: a) the electronic control (55) is arranged on the upper part (12), b) the electro-hydraulic valve device (61) is arranged on the upper part (12).

12. System according to claim 10, characterized in that the receiver (51) for signals for determining height is arranged on the dozer blade (14).

13. System according to claim 12, characterized in that the receiver (51) is arranged on a mast (50) on the dozer blade (14), wherein the mast (50) is in particular bendable and / or elastically flexible.

14. Kit for retrofitting a construction machine (10), namely an excavator with an upper part (12) which is rotatable about a vertical axis on an undercarriage (11) and an adjustable boom (15) on the upper part (12) for receiving and moving a tool (17) and with a dozer blade (14) which is adjustable in height relative to the undercarriage (11) but not adjustable in its transverse inclination, at least with - a receiver (51) for signals for determining height, in particular with a mast (50), - a transmitting unit (53) for transmitting signals to an electronic control unit (55), - the electronic control (55), with a receiving unit (54) for the signals from the transmitting unit (53) and for controlling an electro-hydraulic valve device (61).

15. Kit according to claim 14, characterized by an electro-hydraulic valve device (61) for receiving signals from the electronic control (55) and for controlling a hydraulic volume flow for an indirect or direct height adjustment of the dozer blade (14), 16. Kit according to claim 15, characterized by hydraulic hoses and couplings for connecting the electro-hydraulic valve device (61) to a hydraulic working circuit (57) or pilot control circuit (59) in the construction machine (10).

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