Attachment cutting unit having transverse cutting heads that are angled relative to one another and having output toothed gears with beveloid toothing, and construction machine having such an attachment cutting unit
Patent Information
- Application Number
- EP2023787047
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-10-13
- Filing Date
- 2023-10-06
- Publication Date
- 2025-07-02
AI Technical Summary
Existing excavator-mounted milling machines with side-cutting heads require unnecessary sideways movement and impose excessive mechanical stress on the slewing mechanism, leading to inefficient material removal and high wear, particularly in canal construction and rock excavation where minimizing fines is crucial.
An attachable milling unit with cross-cutting heads angled at 135° to 175°, equipped with a drive spur gear and beveloid-toothed output gears, eliminates the need for a milling chain by allowing closer milling surface contact and reducing unreachable areas, resulting in a simpler, cost-effective, and low-maintenance design.
This configuration enables uninterrupted milling without pendulum movement, reduces mechanical stress, and minimizes fines production, enhancing efficiency and durability in construction applications like canal and rock excavation.
Smart Images
Figure 1.1
Abstract
Description
[0001] Attachment milling unit with cross-cutting heads at an angle to each other and output gears with beveloid toothing as well as construction machine with such an attachment milling unit
[0002] The invention relates to an attachment milling unit with two cross-cutting heads arranged at an angle to one another. The attachment milling unit comprises a housing with an attachment bracket at the rear end of the attachment milling unit for attachment to a movable support arm of a carrier device, preferably an excavator or a similar construction machine. The attachment milling unit further comprises at least one motor and a gear unit which is arranged in the housing and is coupled on the drive side to at least one motor. Finally, two cross-cutting heads which are driven in rotation via the gear unit are attached to both sides of the longitudinal axis of the housing, each cross-cutting head carrying numerous milling cutters and each of the cross-cutting heads having a driven output shaft around which the cross-cutting head rotates.
[0003] The application areas for such a milling attachment system include sewer construction, road construction, special foundation engineering, tunneling, and hydraulic engineering. The milling attachment is used, for example, to break up sealed surfaces, but also for concrete demolition and the removal of certain earth and rock layers.
[0004] Excavator-mounted milling machines are already known; they are designed as cross-cutting head milling machines and are equipped with carbide-tipped round-shank chisels as the cutting tool. When using this type of milling machine, the milling machine must generally be swiveled sideways to break up the material between the cutting heads. The disadvantage of these milling machines is that the cutting width is greater than the actual width of the milling head, which is particularly disadvantageous in canal construction. A further disadvantage of these milling machines is the strain on the excavator's slewing mechanism, which is constantly subjected to high torsional and shear forces during milling.
[0005] Excavator-mounted cutters are also often used for mining soft and medium-hard rocks such as limestone or gypsum. It is particularly important in gypsum mining to keep the fine fraction of the milled material as low as possible. The use of excavator-mounted cutters with lateral cutting heads that are pivoted along the face of the excavation results in the material broken off by the front cutting head being further crushed by the following cutting head.
[0006] DE 100 41 275 B4 discloses a milling system for attachment to hydraulic carrier devices. This system consists of two or more attachment milling machines of the same or different design, each driven separately by a hydraulic motor, and equipped with the same or different tool carriers. The individual attachment milling machines are interchangeably arranged next to one another, one behind the other, or at an angle to one another, at the same or different heights via connecting consoles. This is intended to make material removal in front of the carrier device more efficient. However, this milling system is complex and not very suitable, for example, for trench construction.
[0007] A so-called trencher is known from US 7,096,609 B2, which is equipped with a milling chain. The trencher comprises auger shafts mounted vertically to the direction of travel of the milling chain, which push the removed soil away from the excavated trench. A disadvantage here is the limited applicability of this machine. The trencher is unsuitable for the removal of material over large areas on a wall. Due to its high construction, the trencher is also exposed to high mechanical stress. The forces occur not only in the longitudinal direction of the rotating milling chain, but also perpendicular to the milling chain, particularly when the milling tool hits obstacles such as stones or similar.
[0008] DE 10 2008 041 982 A1 describes an attachment milling system for attachment to a movable support arm of a carrier device. The attachment milling system comprises an attachment console to which rotating cutting heads are attached on both sides of the longitudinal axis of the attachment console. This attachment milling system also comprises a rotating cutting chain with a running direction that runs parallel to the longitudinal axis of the attachment console and that extends between the two cutting heads. Numerous cutting tools are attached to the milling chain and the cutting heads, which describe a cylindrical cutting surface when the cutting heads rotate. The cutting tools of the milling chain form a semi-cylindrical surface at the exposed front end of the milling chain. The front reversal line of the milling chain lies essentially in a plane that is tangent to the cutting surfaces of the two cutting heads.The contact lines between the cutter heads' cutting tools and the surface to be milled are thus located directly next to the contact line between the cutter heads and the milling chain, without any significant gap (which, for machines without a milling chain, is determined by the width of the mounting bracket). These contact lines also conveniently lie in a common plane. While this allows a continuous milling surface to be machined, eliminating the need for a pendulum transverse movement of the milling system, the design of this system is comparatively expensive, and the milling chain, in particular, is subject to significant wear.
[0009] WO 2021 / 239225 A1 describes a drum cutting arrangement for a carrier vehicle. The drum cutting arrangement comprises a main element with a longitudinal extension; a first and a second rotatable cutting drum which are connected to the main element and arranged on opposite sides of the main element; and a drive system which is arranged such that it drives 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. The first axis and the second axis lie with respect to a first plane perpendicular to the longitudinal extension of the main element, wherein an angle is included between the first axis and the second axis. A complex gear system is designed to drive the two cutting drums.The main element has at least one central spur gear with two laterally mounted bevel gears, which interact with two further bevel gears assigned to the cutting drums. In this way, two bevel gear sets (double bevel gear pairing), each consisting of two bevel gears, are arranged symmetrically on opposite sides of the central spur gear. The main element is thus composed of three gears: a central spur gear and two lateral bevel gears, the latter driving the further bevel gears mounted on the shafts of the cutting drums. This design is very complex and prone to repair.
[0010] The object of the invention, based on the prior art, is to provide an improved milling unit for attachment to a movable support arm of a carrier device, which is simpler and cheaper to manufacture, but at the same time allows the creation of a substantially uninterrupted milling surface without requiring a constant pendulum movement of the support arm and the attached milling unit. In particular, the drive gear should be inexpensive and robust. Furthermore, the invention should provide an improved construction machine with such a milling unit.
[0011] This object is achieved by an attachment milling unit according to claim 1 or by a construction machine according to claim 11.
[0012] In the add-on milling unit according to the invention, the two output shafts of the cross-cutting heads are arranged at an angle to one another, each forming an acute angle with the longitudinal axis of the housing on the side facing away from the add-on console. This means that on the side facing the front end of the add-on milling unit, an angle in the range of 135° to 175°, preferably in the range of 160° to 170°, is spanned between the two output shafts of the cross-cutting heads. The cross-cutting heads are therefore inclined towards one another, so that the milling surfaces described by the rotating milling heads are closer to one another on the front-facing side of the cross-cutting heads than on the rear-facing side.In particular, the distance between the described milling surfaces is smaller than the width of the housing, preferably smaller than half the width of the housing of the add-on milling unit on the rearward side of the cross-cutting heads. In the preferred case, the distance between the described milling surfaces is thus only a few centimeters.
[0013] Furthermore, the invention is characterized in that the
[0014] The gear unit comprises a spur drive gear whose axis of rotation runs perpendicular to the longitudinal axis of the housing. The tip lines of the individual teeth of the spur drive gear therefore run transversely to the longitudinal axis of the housing and thus preferably parallel to the milling contact line which is described at the front end of the add-on milling unit when the cross-cutting heads rotate. Furthermore, an output gear with beveloid toothing (also called conical spur gears) is attached to each of the two output shafts of the cross-cutting heads, with the beveloid toothing of each output gear engaging directly in an associated section of the spur toothing of the spur drive gear.
[0015] In this way, the invention makes it possible to reduce the area between the cutting heads that cannot be reached by the milling heads of the cross-cutting heads to a minimum, without the need for a milling chain running between the cutting heads, and at the same time to use a stable, low-wear and low-maintenance gear system equipped with few gear wheels.
[0016] The use of beveloid gearing allows for a significantly simplified and, above all, more compact design compared to the state of the art, since no double bevel gear sets are used and therefore only one spur gear with straight teeth and two beveloid-toothed gears are required, which are driven directly by the straight teeth.
[0017] Preferably, each of the two output gears is also provided with an internal toothing, which is fitted onto an external toothing of a toothed connecting shaft. The connecting shaft connects the internal toothing of the output shaft with the internal toothing of the output gear carrying the beveloid toothing. The output shaft is preferably mounted in an output housing with two tapered roller bearings. The right and left cross-cutting heads are then respectively mounted on the output shaft.
[0018] According to a modified embodiment, the gear unit comprises two parallel partial drive spur gears whose common axis of rotation runs perpendicular to the longitudinal axis of the housing. In this case, too, an output gear with beveloid toothing is mounted on each of the two output shafts, with the beveloid toothing of each output gear meshing with the spur toothing of one of the two drive spur gears.
[0019] Particularly preferably, the milling cutters of each cross-cutting head describe a truncated cone-shaped milling surface as it rotates. In particular, the two truncated cone-shaped milling surfaces at the front end of the add-on milling unit are tangent to a common milling contact plane, i.e., the milling contact line, which is defined in sections by the two adjacent cross-cutting heads, extends in a common plane, which is preferably perpendicular to the longitudinal axis of the housing.
[0020] An advantageous embodiment is characterized in that the motor is a hydraulic motor, which is preferably fastened to a side surface of the housing, but can alternatively be enclosed in the housing. According to a further modified embodiment, the add-on milling unit can comprise two hydraulic motors, which are preferably fastened to opposite side surfaces of the housing. The two hydraulic motors can jointly drive the drive spur gear or drive two independently rotatable drive gears. In the latter case, the two cross-cutting heads are driven independently of one another, which enables separate speed control and can be used, for example, to make one of the two cross-cutting heads rotate more slowly than the other or even to stop it completely under certain conditions.This means, for example, that curved trenches can be milled more easily and with less wear on the cross cutting heads.
[0021] Preferably, the gear unit comprises at least one drive pinion which is in driving engagement with the drive spur gear directly or indirectly via further gears.
[0022] Further advantages and details of the invention will become apparent from the following description of preferred embodiments, with reference to the drawings. They show:
[0023] Fig. 1 is a schematic diagram of a first embodiment of an add-on milling unit according to the invention;
[0024] Fig. 2 is a sectional drawing of a second embodiment of the attachment milling unit.
[0025] Fig. 1 shows a milling unit in a basic view, in which a housing and an attachment bracket, which serves to fasten the milling unit to the support arm of an excavator or the like, are not shown for the sake of simplicity. The housing, which is not shown, however, has a longitudinal extent which is described by a longitudinal axis 01. In this embodiment, the milling unit has a high-torque motor 02, which is attached to one side of the housing and is preferably supplied by the excavator's hydraulic system. Alternatively, an electric motor can be used.
[0026] Arranged within the housing is a gear unit driven by the motor 02. In the illustrated embodiment, the gear unit comprises a drive pinion 03, which is flange-mounted directly onto the motor shaft. Furthermore, the gear unit comprises a drive spur gear 04, whose rotational axis 05 runs perpendicular to the longitudinal axis 01 of the housing.
[0027] The add-on milling unit has two cross-cutting heads 06 which are driven in rotation via the gear unit and are attached to both sides of the longitudinal axis 01 of the housing. They carry numerous milling cutters 07. The milling cutters are only shown on the cross-cutting head on the right in the drawing. As the cross-cutting heads 06 rotate, these milling cutters 07 describe a frustoconical milling surface 08 which is symbolized by dashed lines. Each cross-cutting head 06 is seated on a driven output shaft 09 around which the cross-cutting head rotates. The two output shafts 09 of the cross-cutting heads are arranged at an angle to one another. They preferably span an angle in the range of 150° to 170°.The spanned angle is preferably selected such that the frustoconical milling surfaces 08, with their surface or contact line facing the milling surface, lie in a common plane which is vertical to the longitudinal axis 01 of the housing. In other words, the output shafts 09 each form an acute angle, preferably of approximately 75° to 85°, with the longitudinal axis 01 of the housing at the front end. In order to set the cross cutting heads in rotation, an output gear 10 with beveloid toothing is attached to each output shaft 09, the beveloid toothing of each output gear 10 directly engaging an associated section of the spur toothing of the drive spur gear 04.
[0028] Fig. 2 shows a modified embodiment of the add-on milling unit in a sectional view. The direct engagement of the beveloid toothing of the output gears 10 in the associated lateral areas of the straight toothing of the drive gear 04 is clearly visible here. On the side opposite the circumference of the drive gear 04, the drive pinion 03 engages in the central area of the toothing. This arrangement has the advantage that a uniform load is applied across the toothing surface on the drive gear, and thus uniform wear occurs. While the drive force is introduced in the central area of the toothing, it is transferred to the output gears 10 in the lateral area of the toothing, which is not meshed by the drive pinion 03.The special beveloid toothing ensures that the toothing does not change in the axial direction of the drive gear, i.e., along the individual tooth flanks, thus allowing simple and cost-effective production of the drive gear. Reference symbol.
[0029] 01 Longitudinal axis of the housing 02 Motor
[0030] 03 Drive pinion
[0031] 04 Drive spur gear
[0032] 05 Rotation axis of the drive spur gear
[0033] 06 Cross cutting heads 07 Milling chisels
[0034] 08 Milling surface
[0035] 09 Output shafts of the cross cutting heads
[0036] 10 Output gear
Claims
Patent claims Attachable milling unit comprising: a housing with an attachment bracket at the rear end of the attachable milling unit for attachment to a movable support arm of a carrier device, wherein the housing extends along a longitudinal axis (01); at least one motor (02); a gear unit which is arranged in the housing, is coupled on the drive side to the at least one motor (02) and comprises a drive spur gear (04) whose rotational axis (05) runs perpendicular to the longitudinal axis (01) of the housing;two cross-cutting heads (06) which are driven in rotation via the gear unit and are mounted on both sides of the longitudinal axis (01) of the housing and carry numerous milling cutters (07), each of the cross-cutting heads (06) having a driven output shaft (09) about which the cross-cutting head (06) rotates, the two output shafts (09) of the cross-cutting heads (06) being arranged at an angle to one another and each forming an acute angle with the longitudinal axis (01) of the housing on the side facing away from the attachment bracket; characterized in that an output gear (10) with beveloid toothing is mounted on each of the output shafts (09), the beveloid toothing of each output gear (10) engaging directly with an associated section of the spur toothing of the drive spur gear (04).
2. Attachment milling unit according to claim 1, characterized in that the drive spur gear of the gear unit is divided into two partial drive spur gears which are parallel to one another and whose common axis of rotation runs perpendicular to the longitudinal axis (01) of the housing, and the beveloid toothing of the output gears (10) which are respectively mounted on the output shafts (09) engages in the spur toothing of one of the two partial drive spur gears.
3. Attachment milling unit according to claim 1 or 2, characterized in that each of the two output gears (10) is provided with an internal toothing which is placed on an external toothing of a toothed connecting shaft.
4. Attachment milling unit according to one of claims 1 to 3, characterized in that the milling cutters (07) of each cross-cutting head (06) describe a truncated conical milling surface (08) when it rotates.
5. Attachment milling unit according to claim 4, characterized in that the two truncated conical milling surfaces (08) at the front end of the attachment milling unit are tangent to a common milling contact plane.
6. Attachment milling unit according to one of claims 1 to 5, characterized in that the motor (02) is a hydraulic motor which is attached to a side surface of the housing.
7. Attachment milling unit according to one of claims 1 to 5, characterized in that it comprises two hydraulic motors which are fastened to opposite side surfaces of the housing.
8. Attachment milling unit according to one of claims 1 to 7, characterized in that the gear unit comprises at least one drive pinion (03) which is in driving engagement with the drive spur gear (04) directly or indirectly via further gears.
9. Attachment milling unit according to one of claims 1 to 8, characterized in that on the side facing the front end of the attachment milling unit, an angle in the range of 150° to 170° is spanned between the two output shafts (09) of the cross-cutting heads (06).
10. Attachment milling unit according to one of claims 1 to 9, characterized in that the distance between the milling surface areas (08) described by the cross-cutting heads (06) is smaller than the width of the housing, preferably smaller than half the width of the housing of the attachment milling unit on the rearward-facing side of the cross-cutting heads.
11. Construction machine with a movable support arm having fastening means for attachment units, characterized in that an attachment milling unit according to one of claims 1 to 10 is detachably attached to the fastening means.
12. Construction machine according to claim 11, characterized in that it is designed as an excavator.