Mountable milling unit having transverse cutting heads positioned at an angle to one another and an output gear with beveloid teeth, and construction machine having such a mountable milling unit

Abstract

The present invention relates to an attachment milling (attachment cutting) unit comprising a housing with an attachment bracket for attachment to a movable transport arm of a transport device. The housing extends along a longitudinal axis (01). The attachment milling unit further comprises at least one motor (02) and a transmission unit having a drive spur gear (04) whose rotation axis (05) extends perpendicular to the longitudinal axis (01) of the housing. Two transverse cutting heads (06) are mounted on either side of the longitudinal axis (01) of the housing and are driven in rotation by the transmission unit. The transverse cutting heads (06) carry a number of rotating milling bits (07).

Description

[Technical Field]

[0001] The present invention relates to a mountable milling unit having two horizontal cutting heads positioned at an angle to one another. The mountable milling unit comprises a housing with a mounting bracket at the rear end of the mountable milling unit for attachment to a movable transport arm of a transport device, preferably an excavator or similar construction machine. The mountable milling unit further comprises at least one motor and a transmission unit arranged in the housing and coupled to the at least one motor on the drive side. Finally, two horizontal cutting heads driven in rotation via the transmission unit are mounted on either side of the longitudinal axis of the housing, each carrying a number of milling bits, and each having a driven output shaft around which the horizontal cutting head rotates. [Background technology]

[0002] The fields of use for such attached milling systems are, inter alia, waterway construction, road construction, special foundation construction, tunnel construction or flood control construction, where attached milling cutters are used, for example, for breaking up sealed surfaces, but also for demolishing concrete and breaking up certain soil and rock layers.

[0003] Excavator-mounted milling cutters are already known that are configured as transverse cutting head milling cutters and are equipped with hard metal-tipped round shaft bits as cutting tools. When using this type of milling cutter, it is usually necessary to pivot the milling cutter back and forth to the side, thereby breaking the material between the cutting heads. A disadvantage of these milling cutters is that the cutting width is greater than the actual width of the milling head, which has proven to be particularly disadvantageous in waterway construction. A further disadvantage of these milling cutters is the load on the excavator's pivoting mechanism, which is constantly exposed to large torsional and shear forces during milling.

[0004] Excavator-mounted milling cutters are often used to demolish soft and medium-hard rocks, such as limestone or gypsum. Here, it is particularly important to keep the fines content of the milled material as low as possible, especially when demolishing gypsum. The use of excavator-mounted milling cutters with side cutting heads that are pivoted in the demolition wall undesirably results in the material broken down by the front cutting head being further crushed by the following cutting head.

[0005] German Patent No. 10041275 (DE10041275B4) discloses a milling system for attachment to a hydraulic conveying device, comprising two or more mounting milling cutters of the same or different design, each individually driven by a hydraulic motor, with the same or different tool carriers. The individual mounting milling cutters are interchangeably arranged via connecting brackets, adjacent to one another, behind one another, or at an angle to one another, at the same or different heights. This would desirably enable more efficient material removal in front of the conveying device. However, this milling system is expensive and not particularly suitable for, for example, trench construction.

[0006] U.S. Patent No. 7,096,609 discloses a so-called trencher equipped with a milling chain. The trencher has a screw shaft mounted perpendicular to the direction of travel of the milling chain, which pushes the removed soil out of the excavated trench. One drawback is that the usability of this machine is limited. Trenchers are not suitable for large-scale demolition of walls. Furthermore, due to their highly realized structure, trenchers are exposed to high mechanical stresses. Here, forces occur not only in the longitudinal direction of the surrounding milling chain, but also perpendicular to it, especially when the milling tool strikes an obstacle such as a stone or similar.

[0007] German Patent Application Publication No. 102008041982 describes a mounting milling system for attachment to a movable transport arm of a transport device. The mounting milling system includes a mounting bracket, to which rotating cutting heads are attached on both sides of the longitudinal axis of the mounting bracket. The mounting milling system further includes a circumferential rotating milling chain with a direction of travel running parallel to the longitudinal axis of the mounting bracket and extending between the two cutting heads. A number of milling bits are attached to the milling chain and the cutting heads, which describe a cylindrical outer milling surface when the cutting heads rotate. The milling bits of the milling chain form a semi-cylindrical outer surface at the exposed front end of the milling chain. Here, the front reversal line of the milling chain is substantially in a plane tangent to the outer milling surfaces of the two cutting heads. The contact line between the milling bit of the cutting head and the surface to be milled is therefore directly adjacent to the contact line of the milling bit of the milling chain, without the significant gap that would be determined by the width of the mounting bracket in a system without a milling chain. Advantageously, these contact lines are also in a common plane. Thus, an uninterrupted milling surface can be machined, thereby eliminating the need for the pendulum lateral movement of a mounted milling system, but the construction of this system is relatively expensive and the milling chain in particular is subject to strong wear.

[0008] WO 2021 / 239225 describes a drum cutting device for a transport vehicle. The drum cutting device includes a main element having a longitudinal extension; first and second rotatable cutting drums connected to the main element and arranged on opposite sides of the main element; and a drive system arranged to drive the first and second cutting drums. The first cutting drum is rotatable about a first axis, and the second cutting drum is rotatable about a second axis. With respect to a first plane, the first and second axes are perpendicular to the longitudinal extension of the main element, and an angle is formed between the first and second axes. A complex transmission is formed to drive both cutting drums. The main element has at least one central spur gear with two bevel gears attached to its sides, which interact with two additional bevel gears associated with the cutting drums. In this way, two bevel gear sets (double bevel gear pairs), each consisting of two bevel gears, are symmetrically arranged on opposite sides of the central spur gear. The main element therefore consists of three gears: a central spur gear and two bevel gears at the sides, which drive further bevel gears on the shaft of the cutting drum. This construction is very expensive and prone to repairs. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] German Patent No. 10041275 (DE10041275B4) [Patent Document 2] U.S. Patent No. 7,096,609 [Patent Document 3] German Patent Application Publication No. 102008041982 [Patent Document 4] International Publication No. 2021 / 239225 Summary of the Invention [Problem to be solved by the invention]

[0010] The object of the present invention is to provide, starting from the prior art, an improved mountable milling unit for mounting on a movable carrier arm of a transport device, which mountable milling unit can be manufactured more easily and inexpensively, and at the same time makes it possible to produce a substantially uninterrupted milling surface, for which a constant pendulum movement of the support arm and the mountable milling unit fixed thereto is not required. In particular, it is desirable for the drive transmission to be realized inexpensively and robustly.

[0011] Furthermore, the present invention desirably provides an improved construction machine having such an attached milling unit. [Means for solving the problem]

[0012] This problem is solved by an attachable milling unit according to claim 1 or a construction machine according to claim 11.

[0013] In the case of the mountable milling unit according to the present invention, the output shafts of the horizontal cutting heads are arranged at an angle to each other, forming an acute angle with the longitudinal axis of the housing on the side facing away from the mountable bracket. This results in an angle between the output shafts of the horizontal cutting heads on the side facing the front end of the mountable milling unit ranging from 135° to 175°, preferably 160° to 170°. The horizontal cutting heads are therefore inclined relative to each other, so that the milling planes traced by the rotating milling heads are closer to each other on the forward-facing side of the horizontal cutting heads than on the rear-facing side. In particular, the distance between the traced milling planes on the rear-facing side of the horizontal cutting heads is less than the width of the housing, preferably less than half the width of the mountable milling unit housing. Therefore, in preferred cases, the distance between the traced milling planes is only a few centimeters.

[0014] The invention is further characterized in that the transmission unit comprises a drive spur gear, the rotation axis of which runs perpendicular to the longitudinal axis of the housing. The head lines of the individual teeth of the drive spur gear therefore run transversely to the longitudinal axis of the housing, and thus preferably parallel to the milling contact line described during rotation of the transverse cutting head at the front end of the attached milling unit. Furthermore, output gears (also called conical spur gears) with beveloid teeth are mounted on both output shafts of the transverse cutting heads, and the beveloid teeth of each output gear directly engage with the associated portion of the spur teeth of the drive spur gear.

[0015] In this way, the invention minimizes the areas between the transverse cutting heads that are not reachable by the milling heads of these cutting heads, so that a milling chain running between the cutting heads is not necessary, and at the same time makes it possible to use a stable, low-wear and low-maintenance transmission equipped with fewer gears.

[0016] The use of beveloid teeth allows for a significantly simplified and, above all, more compact construction compared to the prior art, since no double bevel gear set is used and therefore only one spur gear with straight teeth and two beveloid toothed gears driven directly by the straight teeth are required.

[0017] Preferably, each of the output gears further has internal teeth that fit over the external teeth of the toothed connecting shaft. The connecting shaft connects the internal teeth of the output shaft with the internal teeth of the output gear, which bears the beveloid teeth. The output shaft is preferably mounted in an output housing with two tapered roller bearings. The right or left transverse cutting head is then mounted on the output shaft, respectively.

[0018] According to a modified embodiment, the transmission unit comprises two part-drive spur gears positioned parallel to one another, their common axis of rotation running perpendicular to the longitudinal axis of the housing, and in this case too, on both output shafts, respectively, an output gear with beveloid teeth is mounted, the beveloid teeth of each output gear respectively engaging with the spur teeth of one of the two drive spur gears.

[0019] Particularly preferably, the milling bit of each transverse cutting head describes a frustoconical milling outer surface during its rotation, in particular both frustoconical milling outer surfaces adjoining each other at the front end of the attached milling unit in a common milling contact plane, i.e. the milling contact line partially defined by both transverse cutting heads located adjacent to each other extends in a common plane that is preferably perpendicular to the longitudinal axis of the housing.

[0020] An advantageous embodiment is characterized in that the motor is a hydraulic motor, preferably fixed to a side surface of the housing, or alternatively, may be housed within the housing. According to a further modified embodiment, the attached milling unit may include two hydraulic motors, preferably fixed to opposite side surfaces of the housing. Both hydraulic motors can be used together to drive a drive spur gear, or they can drive two drive gears that can rotate independently of each other. In the latter case, both transverse cutting heads are driven independently of each other, which allows separate speed control, which can be used, for example, to rotate one of the transverse cutting heads slower than the other or even completely stop it under certain conditions. Thus, for example, curved grooves can be milled more easily and with less wear on the transverse cutting heads.

[0021] Preferably, the transmission unit comprises at least one drive pinion in driving engagement with the drive spur gear either directly or indirectly via a further gear.

[0022] Further advantages and details of the invention will become apparent from the following description of preferred embodiments with reference to the drawings. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a basic view of a first embodiment of an attachable milling unit according to the invention; [Figure 2] FIG. 10 is a cross-sectional view of a second embodiment of the attached milling unit. DETAILED DESCRIPTION OF THE INVENTION

[0024] 1 shows a basic diagram of a mounted milling unit, and for simplicity, the housing and mounting bracket used to secure the mounted milling unit to a support arm of an excavator or the like are not shown. The housing, which is not shown, however, has a longitudinal extension represented by a longitudinal axis 01. In this embodiment, the mounted milling unit has a high-torque motor 02 attached to one side of the housing and preferably powered by the excavator's hydraulic system. Alternatively, an electric motor could be used.

[0025] Arranged inside the housing is a transmission unit driven by a motor 02. In the embodiment shown, the transmission unit comprises a drive pinion 03 flanged directly onto the motor shaft. Furthermore, the transmission unit comprises a drive spur gear 04, the rotation axis 05 of which runs perpendicular to the longitudinal axis 01 of the housing.

[0026] The attached milling unit has two horizontal cutting heads 06 mounted on either side of the longitudinal axis 01 of the housing and driven in rotation via a transmission unit, carrying a number of milling bits 07, only the horizontal cutting head located on the right side of the drawing. During rotation of the horizontal cutting heads 06, the milling bits 07 describe a frustoconical milling outer surface 08, represented by dashed lines. Each horizontal cutting head 06 is mounted on a driven output shaft 09, around which the horizontal cutting head rotates. The output shafts 09 of the horizontal cutting heads are arranged at an angle to each other. Preferably, the output shafts 09 diverge at an angle ranging from 150° to 170°. The divergence angle is preferably selected so that the frustoconical milling outer surfaces 08, at their outer surfaces or contact lines facing the milling surface, lie in a common plane perpendicular to the longitudinal axis 01 of the housing. In other words, the output shaft 09 forms at its front end an acute angle, preferably between about 75° and 85°, with the longitudinal axis 01 of the housing.

[0027] To rotate the transverse cutting heads, output gears 10 having beveloid teeth are mounted on the output shafts 09, respectively, and the beveloid teeth of each output gear 10 directly engage with an associated portion of the spur teeth of the drive spur gear 04.

[0028] FIG. 2 shows a cross-sectional view of a modified embodiment of the mounted milling unit. It can be clearly seen here that the beveloid teeth of the output gear 10 directly engage with the corresponding lateral regions of the straight teeth of the drive gear 04. On the opposite circumferential side of the drive gear 04, the drive pinion 03 engages in the central region of the teeth. This arrangement has the advantage of uniform loading across the tooth flanks of the drive gear, and therefore uniform wear. While the driving force is introduced in the central region of the teeth, it is released to the output gear 10 in the lateral regions of the teeth that are not engaged with the drive pinion 03. However, the special beveloid teeth ensure that the teeth do not vary in the axial direction of the drive gear, i.e., along the individual tooth flanks, thereby allowing for easy and inexpensive production of the drive gear. [Explanation of symbols]

[0029] 01...Longitudinal axis of housing, 02...Motor, 03...Drive pinion, 04...Drive spur gear, 05...Rotation axis of drive spur gear, 06...Transverse cutting head, 07...Milling bit, 08...Outer surface of milling cutter, 09...Output shaft of transverse cutting head, 10...Output gear

Claims

1. a housing having a mounting bracket at the rear end of the mounted milling unit for attachment to a movable transport arm of a transport device, said housing extending along a longitudinal axis (01); at least one motor (02); a transmission unit arranged in said housing, coupled on the drive side to said at least one motor (02), and comprising a drive spur gear (04), the rotation axis (05) of which runs perpendicular to said longitudinal axis (01) of said housing; - two transverse cutting heads (06) mounted on either side of the longitudinal axis (01) of the housing and carrying a number of milling bits (07), driven in rotation via the transmission unit, each having a driven output shaft (09) about which it rotates, the output shafts (09) of both transverse cutting heads (06) being arranged at an angle to one another and forming an acute angle with the longitudinal axis (01) of the housing on the side facing away from the mounting bracket; In a mounted milling unit, An output gear (10) having beveloid teeth is mounted on each of the output shafts (09), characterised in that the beveloid teeth of each output gear (10) directly engage with an associated portion of the spur teeth of the drive spur gear (04), Mountable milling unit.

2. 2. A mounted milling unit according to claim 1, characterized in that the drive spur gear of the transmission unit is divided into two part-drive spur gears lying parallel to each other, their common axis of rotation running perpendicular to the longitudinal axis (01) of the housing, and the beveloid teeth of the output gears (10) mounted respectively on the output shafts (09) engage with the spur teeth of one of both part-drive spur gears.

3. 3. A milling unit according to claim 1 or 2, characterized in that both output gears (10) are each provided with internal teeth fitted onto the external teeth of a toothed connecting shaft.

4. 4. A mountable milling unit according to claim 1, wherein the milling bit (07) of each transverse cutting head (06) describes a milling outer surface (08) in the shape of a truncated cone when it rotates.

5. 5. A mountable milling unit according to claim 4, characterized in that both of said frustoconical milling outer surfaces (08) are in contact with a common milling contact plane at the front end of said mountable milling unit.

6. 6. The attached milling unit according to claim 1, wherein the motor (02) is a hydraulic motor fixed to a side surface of the housing.

7. The mountable milling unit according to any one of claims 1 to 5, characterized in that the mountable milling unit comprises two hydraulic motors fixed to opposite side surfaces of the housing.

8. 8. The mounted milling unit according to claim 1, wherein the transmission unit comprises at least one drive pinion (03) in driving engagement with the drive spur gear (04) either directly or indirectly via a further gear.

9. 9. A mountable milling unit according to any one of claims 1 to 8, characterized in that, on the side facing the front end of the mountable milling unit, there is an angle spread between both output shafts (09) of the transverse cutting head (06) in the range of 150° to 170°.

10. 10. A mountable milling unit according to any one of claims 1 to 9, characterized in that the distance between the milling outer surfaces (08) described by the transverse cutting heads (06) is, on the side facing rearward of the transverse cutting heads, smaller than the width of the housing, preferably smaller than half the width of the housing of the mountable milling unit.

11. A construction machine having a movable transport arm with fixing means for an attachable unit, characterized in that an attachable milling unit according to any one of claims 1 to 10 is removably attached to the fixing means.

12. 12. Construction machine according to claim 11, characterized in that the construction machine is configured as an excavator.

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