EP2350391B1

EP2350391B1 - Road milling machine with milling drum with different cutting widths

Info

Publication number: EP2350391B1
Application number: EP08874993.2A
Authority: EP
Inventors: Karl MÖTZ
Original assignee: Marini SpA
Current assignee: Marini SpA
Priority date: 2008-10-27
Filing date: 2008-10-27
Publication date: 2018-01-24
Anticipated expiration: 2028-10-27
Also published as: EP2350391A1; WO2010048967A1

Description

Technical Field

The present invention concerns a milling machine with variable width milling drum and in particular a milling machine for asphalt, concrete and other materials used for road pavings according to the characteristics of the pre-characterizing part of claim 1.

Background Art

A road milling machine is a self-propelled machine, of known technology, finalized to the demolition of road pavements by means of milling with rotating milling drum. The road milling machines generally are equipped with fixed width milling drums contained in a housing opened downwardly to ensure the contact of said milling drum with the surface to mill and opened frontally for the flow of the milled material outside of the milling drum housing. To change the milling width it is necessary to replace not only the milling drum, but also a series of equipments dependent from the sizes of the milling drum itself.
Solutions concerning milling drums modifiable with different cutting widths are also known, which solutions however generally involve difficulties in the assembling or modification and long set-up times.
EP0694651 , also published as WO 01/04422 , discloses an improvement of a cold road milling machine having means for the advancement of the machine and a milling drum mounted on the machine for cutting a certain material width along the path of the machine and a conveyor mechanism for transporting the milled material generated by the cut of the milling drum away from the machine, the improvement including:

a. a rotating milling drum divided into two or more sections with at least one of said sections being divided into segments.
b. means for the assembly of said segments on said milling drum whereby when said segments are mounted to said milling drum, the width of cut of the milling drum is increased, and when said segments are removed from said milling drum, the width of cut is decreased;
c. a drive train for providing power to rotate said milling drum;
d. said drive train having a power input end and a power output end;
e. a first section of the milling drum being connected at the power output of the transmission train and substantially flush mounted with reference to the drum end opposite to the power input of the entry of power of the drive train, and one or more additional segmented sections.
f. means to connect the segments of said additional sections to said first section of the drum, where said additional segmented sections are mounted between the first section of the drum and the power input of the drive train.
g. a planetary gear device that transmits the power output to the milling drum, a transmission shaft that comes through the milling drum and connected to the planetary gear, milling means surrounding said planetary gear.

US5722789 discloses an improvement of a cold road milling machine, said machine including a drive train having an end for the intake of the power at one side of the machine and an end for the delivering of the power on the other side of the machine, said intake end of the power of said drive train being connected to a power source. Said delivering end of the power of said drive train connected to a reduction gear mounted within an appropriate housing, said housing of the reduction gear having opposite ends, an end of said housing of the reduction gear being generally flush mounted on the side of the machine corresponding to the power delivering side, said housing of the reduction gear being mounted for the rotation, in relation to said machine, of a cylinder that extends from the opposite end of said housing of the reduction gear towards the other side of said machine, means to command the rotation of said cylinder, said improvement including:

a. a set of milling drums, each drum in said set of milling drums having opposing ends and being of a different length
b. each drum in said set of milling drums being divided into segments
c. means for releasably connecting one end of any selected one drum of said set of milling drums to said one end of said housing of the reduction gear
d. a connector element on the other end of at least one of said drums in said set of milling drums whereby said at least one of said drums can be releasably connected at its other end to said drum

EP1520076 discloses a self-propelled road milling machine comprising a machine chassis, inside of which a milling drum is mounted in such a way to be rotary between side-walls which are orthogonal to the axis of the milling drum, the milling drum, which has a drum base body and a milling pipe, being suitable to be commanded by means of control means that are supported on the exterior of the side-wall on the power intake side and by means of a reduction gear, and the side-wall situated on the opposite side relative to the side-wall on the power intake side, this being easily demountable for changing alternative milling drums, having different milling widths, and defining the zero-side of the machine against which a face of the milling drum is in abutment in an approximately flush way to allow the milling in proximity to a border, characterised in that:

a. the reduction gear is mounted on the intake side of the transmission
b. the reduction gear includes on the exit a transmission element, which is mounted on the inside of the side-wall on the input side of the transmission and whose external surface forms a seat for elements of the milling drum which may be slided on it starting from the zero-side
c. the drum base body is coupled to the reduction gear at the exit free frontal face of the transmission without opposing to the sliding of the elements of the milling drum.

EP1194651 discloses a milling drum comprising a drum base body driven by a milling drum drive device via a transmission unit, a one-piece tubular milling drum coaxially slidably mounted from one side on the drum base body in a manner allowing exchange thereof, the milling drum carrying cutting tools on the outer surface, the milling drum includes fastening elements radially projecting from an inner surface of the milling drum by which the milling drum can be secured in a rotationally fixed manner to the drum base body, said milling drum drive device being placed in correspondence of a side of said drum base body opposite to said side, said fastening means being provided on at least one side of said milling drum, said milling drum being connected to a side-wall of said drum base body and being radially supported on the other side, said fastening means being connected to the base body including the transmission unit integrated on it, said transmission unit being mounted at the end of the base body with the exit directed towards the control group, the input being controlled by a transmission shaft passing through the base body, said base body being supported by two side-walls of the milling drum housing, said housing being provided with an opening that allows the access to the fixing elements between the milling drum and the control group without dismounting parts of the machine. On the axial end of the milling drum opposite to the transmission unit, a movable bearing is provided which by means of a guide member is centrically supported in a recess of the side wall. The guide member and the recess can have conical shapes adapted to each other so that the roller base body with the movable bearing is centrically supported.
DE 10 2004 025567 discloses a road milling machine in which the milling drum can be exchangeably mounted between the side walls of a milling drum housing and it is rotationally driven by the cutting roller drive via the transmission. The cutting roller can be exchanged together with at least one part of one side wall and optionally the transmission as one unit.

Problems of the prior art

EP0694651 , also published as WO 01/04422 , though allowing a simplified variation of the milling width of the machine that does not require any replacement of parts related to the transmission, however requires the carrying out of different operations in the changing phase of the milling width, as the milling drum results subdivided into two or more sections, each of the sections able to make the variation of the milling width being divided in segments, each of which, in the illustrated embodiment, covers an arc of 120 degrees. When said sections are not utilized, that is one operates with a reduced milling width, for each of them it is necessary to mount in their respective places a rotating blades wheel suitable to push the milled material toward the collecting belt for facilitating its removal from the inside of the milling drum housing. Said blades wheel is also divided into a number of segments corresponding to the number of segments forming the additional sections of the milling drum and, therefore, in the shown embodiment, three segments each of which covering an arc of 120 degrees. Both the segments of the rotating blades and the segments of the additional sections of the milling drum are screwed by means of bolts on radial protrusions of the transmission shaft. Said bolts are therefore exposed to the milled material, and for this reason at the moment of the change of the milling width it will be necessary to clean the rotating blades and/or the sections of the milling drum to be replaced in order to have access to said bolts, remove all of the bolts of each segment of each section whereon one must intervene, remove the blade segments to replace them with the segments of the milling drum or vice-versa, and screw again the bolts. Said operation requires however a long intervention time because of the need to operate on more then one segment, the intervention times being possibly further increased because of the wear and tear of the bolts caused by the milled material. Moreover the replacement operation of the milling elements occurs accessing the milling drum housing from the back, obliging the operator to work in a narrow space and in uncomfortable working positions. The illustrated preferred embodiment, moreover, provides that the first section, the one defining the minimum milling width, is made in a single piece coaxial to the reduction gear, so that if it is necessary to replace said first section for wearing or damage, it is anyway required the dismounting of the reduction gear itself, with consequent considerable lengthening of the intervention time. Moreover the first milling section, being always in use even in the case of greater milling widths, results subject to a greater wearing compared with the added sections, compromising the quality of the milling itself and requiring a more frequent replacement of the tools of said first section compared with the others.
US5722789 presents an embodiment similar to the previous one in which all the sections, including the first one, are subdivided into two opposite segments each of which covering an arc of 180 degrees, rather than three segments, said segments being reciprocally fixed and not on radial protrusions of the transmission shaft. For this reason the transmission of the power to said sections occurs by means of a couple of opposite keys each of them transmitting the motion to the respective corresponding section. These keys are screwed in suitable seats present on the supporting rotating cylinder and are housed in different positions depending on the milling width to be adopted. This solution, though reducing the number of parts to be replaced for each section, requires also the moving of the keys transmitting the motion to said sections, therefore involving anyway a high number of pieces to be replaced. Moreover said solution anyway involves the need to operate on different segments and it also results affected by the problem of the inaccessibility of the fixing bolts both of the keys and of the segment themselves, said bolts being exposed directly to the milled material and therefore requiring a preliminary cleaning operation in order to be able to have access and intervene on them. Moreover the replacement operation of the milling elements occurs accessing the milling drum housing from the back, obliging the operator to work in a narrow space and in uncomfortable working positions. Moreover the first milling section, being always in use, even in the case of greater milling widths, results subject to a greater wearing compared with the added sections, compromising the quality of the milling itself and requiring a more frequent replacement of the tools of said first section compared with the others.
EP1520076 though solving some of the abovementioned problems about the previous solutions, as soon as it uses different milling drums with overall length corresponding to the desired cutting width which can be sideways removed with reference to the machine, has other disadvantages about the positioning of the reduction gear, that is mounted on the left-hand side of the machine involving the presence of an element of transmission able to ensure the possibility to insert the lower width milling drums in such a way that they are flush with the right side of the machine. An additional protection for the reduction gear is needed when operating with the lower width milling drums in order to prevent the milled material to wear the reduction gear itself. Said element of transmission and said additional protection constitute additional rotating masses with consistent size. Moreover, the replacement or inspection of the reduction gear requires the operator to work in a narrow space and in uncomfortable working positions, being exposed to the milled material present in the mill-drum housing.
EP1194651 though solving some of the abovementioned problems about the previous solutions, as soon as it uses different milling drums with overall length corresponding to the desired cutting width which can be sideways removed with reference to the machine, and though having the reduction gear unit mounted on the right side of the machine, has other disadvantages from the point of view of the fixing of the milling drum. In fact, for milling drums with greater width, apart from the fixing point on such element of transmission integral with the reduction gear, an additional support is necessary that in the case of the disclosed invention is realized at the external surface of the base body of the drum itself by means of a movable radial support ring. Said radial support ring can be shifted in various positions depending on appropriate seats realized on the external part of the base body of the drum. If one works with milling drums with lower widths, the seats that are not utilized must be protected from the exposure to the milled material in order to avoid the clogging by means of appropriate protection plates fixed on the seats by means of screws, these screws themselves therefore being exposed to the milled material and subject to clogging due to the same, which lengthens the replacement time of the milling drum when said annular support and said protection plates must be shifted. On the side opposite to the transmission unit, the milling drum is supported by means of a movable bearing which in turn is supported by means of a guide member engaging with a recess of the side wall. Being the side wall hinged to allow the extraction of the milling drum, the guide member and the recess engagement is a conical engagement. The use of a conical engagement can cause a misalignment of the milling drum during the installation, for example due to the presence of residues of the milled material, thus causing an obstacle during the installation of the milling drum increasing the replacement time and causing the presence of additional vibrations due to the axial misalignment of a considerable rotating mass and wearing of the supports.
Therefore, all of the prior art systems, have in common the characteristic that, when the replacing of the milling drum with another one having a different width is needed, the operator must access the milling drum housing to substitute some parts of the machine or to move / slide some supports of the milling drum. These operations must be performed working in a narrow space and in uncomfortable working positions, being exposed to the milled material present in the mill-drum housing. Moreover, in all of the prior art systems, said parts to be substituted or moved / slided are exposed to the milled material and subject to clogging due to the same, which lengthens the replacement time of the milling drum.

Aim of the invention

The invention has the following aims:

replace a milling drum of a certain cutting width with a different width drum, without replacing other parts and making this operation fast and easy also for unskilled personal.
replacement of the milling drum width with a different width drum, without the need to adjust the position of adjustable supports
replace a milling drum of a certain cutting width with a different or same width drum, but with different spacing of the tools, without replacing other parts and making this operation fast and easy also for unskilled personal.
not penalize the milling depth with respect to the one obtainable with the milling drum with maximum width.
allow the milling "flush to the wall" on the right side of the machine for any width of the milling drum
allow a correct and fast alignment of the milling drum in the axial direction.

Advantageous effects of the invention

The proposed solution according to the present invention as defined in independent claims 1 and 11 presents advantages from the point of view of the handiness in the replacement of the milling drum for which a uniform wearing along its whole length is advantageously guaranteed contrarily to the systems of the prior art that provide milling drums divided into individually disassemblable sections.
Moreover the exposure to the milled material of the elements on which the operator must intervene during the operations of replacement of the milling drum is advantageously avoided.
During the replacement of the milling drum no modification is required in the supports of the milling drum itself or in their position, thus reducing the replacement time and avoiding the need for the operator to work in a narrow space and in uncomfortable working positions.
All the replacement operations can be performed acting from the outside of the milling drum housing, reducing the risk of accidents.
The inspection or replacement of the reduction gear is easier.

Description of a preferred embodiment of the milling machine

An embodiment of the invention is now described, by way of example only, with reference to the accompanying drawings in which:

Fig. 1 represents a side view of a milling machine.
Fig. 2 represents a side view of the milling machine of figure 1, partially in section to show some of the internal components.
Fig. 3 represents the rear sectional view of a typical system supporting a full width milling drum according to the prior art.
Fig. 4 represents the rear sectional view of the system supporting a full width milling drum which does not represent the present invention.
Fig. 5 represents the rear sectional view of the system supporting a reduced width milling drum according to the present invention.
Fig. 6, 7, 8, 9, 10 represent top sectional views of the system supporting the milling drum, according to the present invention, showing the removing operation of the milling drum.
Fig.11 represents a sectional view of a reduced width milling drum milling along with the fixing of the reduction gear to the milling drum frame, according to the present invention.
Fig. 12 represents an enlarged view of the detail A of Fig. 6, showing a sectional view of the support of the milling drum on the left-hand side of the same, according to the present invention.
Fig.13 represents the rear view of the rear mouldboard closing the housing of the milling drum.

Detailed description of the milling machine with reference to the drawings

Because of the wearing of the pavement due to atmospheric causes apart from the continuous passage of vehicles, the periodical renewal of the same is necessary. For such renewal operation the removal of the old pavement is generally required or at least the removal of its upper layer to avoid the creation of dangerous steps due to the laying of the new pavement at the connection points with parts of pavement previously applied and still in good conditions. In some cases the removal of the pavement is absolutely necessary as in the case of bridges, for which the removal of the old pavement must be carried out before the laying of the new pavement in order to avoid the increasing of the weight held up by the bridge itself and due to the subsequent repaving one following the other in the course of time, or in the case of railway crossings with reference to which the same height of the pavement must be held in order to avoid dangerous steps that would compromise the grip of the vehicles. The milling machines answer to this need, being machines specially conceived for the removal of the old pavement before the laying of the new material. The road milling machine (Fig. 1, 2) consists of a self-propelled chassis (1) supported on tracks (2), or wheels, generally equipped with hydraulic drives that pull power from a diesel engine.
The milling drum (3) is supported by the chassis (1), transversely to the advancement direction of the machine and is activated by the diesel engine through a mechanical transmission, or by a hydraulic transmission. The tracks (2), or wheels, are connected to telescopic columns (4), by means of which the chassis (1) is brought to height and set to obtain the correct milling profile. The material milled by the milling drum (3) is removed by a system of one or two conveyor belts (5, 6) and it can be discharged at the forepart or at the rear part of the machine. In the first case the material is discharged on means of transportation that precedes the milling machine, while in the second case the means of transportation follows the milling machine proceeding in reverse motion.
The description of the invention refers to its application on a road milling machine with frontal discharge of known technology (Fig. 1, 2), in which the milling drum (3) is housed in a milling drum housing (7). Referring to the advancement direction during operation, the milling drum housing (7) is provided with a movable rear mouldboard (8), provided with scraper tools for cleaning of the milled surface, and is provided with two movable side plates (9a, 9b) in contact with the road surface, with floating action or slightly forced downwards. However, it will apparent to one skilled in the art that the invention object of the present application is applicable also to milling machines with rear discharge.
In the forepart of the milling drum housing (7) a discharge opening (10) is provided, which allows the discharge of the milled material onto a first conveyor belt (5), generally identified as collecting belt. Said collecting belt (5) has its rear part supported by a device commonly known with the name of "pressure bar" (11), generally kept in more or less forced contact with the surface to be milled, and the forepart sliding on a support connected to the chassis (1) of the machine.
The rear mouldboard (8) can be vertically moved and can rotate around a horizontal axis. The vertical movement allows to maintain the mouldboard in contact with the milled surface with a floating, or forced, action but for particular operative needs the mouldboard may also be held partially raised to leave the material flow below it. Its lower edge is provided with scraper tools for cleaning the milled surface. The rotational motion around a hinge with horizontal axis allows the opening of the mouldboard to access the tools of the milling drum (3) for maintenance operations or for its inspection.
A typical system of the prior art for supporting the milling drum and for the transmission of its rotational motion around an axis perpendicular to the advancement direction of the machine (Fig. 3) is provided with a pulley (12) (power take-off), placed on the left-hand side of the machine, which receives the motion from the diesel engine through a clutch and a trapezoidal belts transmission. The pulley (12) is keyed on the input shaft of the reduction gear (13), constrained to the milling drum housing (7) by the fixing flange (15) of the reduction gear on the milling drum housing and engaged with the frame of the milling drum (3) by the flange (16). The reduction gear (13) therefore constitutes the support of the milling drum (3) on the left-hand side of the machine. On the right side the milling drum (3) is supported by the milling drum housing (7) by means of the support (14), engaged with the frame of the milling drum by means of the flange (17). Said reduction gear (13) is necessary to convert the rotation with high number of revolutions per minute given by the engine into a rotation of the drum having the required torque for milling the road surface.
The road milling machines are generally equipped with fixed width milling drums. To change the milling width it is necessary to replace not only the milling drum but also a series of equipments depending on the sizes of the drum itself. Solutions concerning milling drums modifiable with different cutting widths are also known, which solutions however generally involve difficulties in the assembling or modification and long set-up times as previously disclosed. In Fig. 4 which does not represent the present invention, the reduction gear (19) is fitted on the right side of the machine, in order to allow a fast and simple installations of milling drums even with relatively small width, but able to cover the overall dimensions of the reduction gear. In fact, in the case of the mounting of milling drums with reduced width, they must necessarily be mounted at the right side of the machine because it is generally necessary to perform millings flush to the right side, because the presence of obstacles as curbs, guard-rails, platforms, etc. precludes the machine to move beyond the limit imposed by such obstacles and the milling flush to them would be impossible if the milling drum with lower width is mounted at a position even a little sideways re-entered with respect to the right-hand edge of the machine.
The eventual protrusion of the overall dimensions of the reduction gear beyond the left-hand flush of the milling drum would constitute a limit for the milling depth, because said projection of the reduction gear could interfere with the road surface.
The transmission shaft (20) transfers the motion from the pulley (12) to the reduction gear (19) that in the preferred embodiment is a planetary reduction gear with an input passing through hollow shaft. The reduction gear (19) is rigidly connected to the right-hand side wall (18) of the drum housing (7) by means of an centring auxiliary ring (21) that, along with the calibrated screws (24) and the screws (25) constitutes the reaction constraint, said reduction gear (19) being connected to the frame of the milling drum (3) by means of the fixing screws (26). In the solution object of the invention, on the left-hand side (Fig. 12) the milling drum (3) is provided with a milling drum collar (22) sliding in contact with the rotating support (36) including a low friction ring (27), a rotating ring (28) and a bearing (30): the low friction ring (27), made of low friction material, centres the drum over the rotating ring (28), in turn supported by the bearing (30).
So during the insertion and extraction steps, said milling drum collar (22) slides longitudinally over said low friction ring (27) with respect to the axis the of said milling drum (3), said milling drum collar (22) having a length corresponding to the difference between the cutting width of milling drum and the maximum milling drum cutting width.
The transmission shaft (20) is supported on the right-hand side by said reduction gear (19) and on the left-hand side by a bearing (33).
A sealing means (29) prevents any dust to enter into the annular chamber between the rotating support (36) and said reduction gear (19).
In a preferred solution the bearing (30) is lubricated by grease, supplied by means of the grease conduit (37), with discharge of the exceeding volume through a sealing labyrinth (34), whilst the bearing (33) is in oil bath.
The milling drum collar (22) does not constitute a limit to the cutting depth as its distance "B" (Fig. 5) from the ground level is higher than the distance "A" from ground level of the auxiliary ring (21). Although the milling drum collar (22) is represented as being an integral part with the milling drum (3), in a less preferable embodiment said milling drum collar (22) is mounted on said milling drum (3) in a dismountable way by means of fixing means (e.g. screws) through a flange radially protruding from an internal surface of said milling drum (3).
Said auxiliary ring (21) is provided in order to consent the free opening of the right-hand side wall (18) around a vertical hinge (23): this solution considerably facilitates the replacement of the milling drum. The reaction to the radial force and to the torque applied to the milling drum is obtained by the friction of said auxiliary ring (21) against the right-hand side wall (18) by means of two series of fixing screws, conventional screws (24) and calibrated screws (24), namely tight tolerance screws for the centring of the milling drum.
The replacement of the milling drum (3) is carried out as shown in figures 6, 7, 8, 9, 10 and consists of the following steps with the milling drum held up by milling drum support means (not represented):

a- removing the screws (25) fixing the reduction gear (19).
b- removing the calibrated screws (24) fixing the auxiliary ring (21).
c- removing the right-hand wall screws (35) fixing the right-hand wall to the frame of the drum housing (7).
d- extraction of the milling drum (3) together with the reduction gear (19) by pulling back the milling drum support means.
e- removing the fixing screws (26) which fix the reduction gear (19) to the frame of the milling drum.
f- Removing the reduction gear (19) from the milling drum (3)

Fig. 11

It will be apparent from the above description that the solution object of the present invention avoids the need for the operator to work in a narrow space and in uncomfortable working positions during the replacement of the milling drum, no modification being required in the supports of the milling drum itself or in their position. All operations can be performed acting from the outside of the milling-drum housing (7) thus reducing the replacement time, avoiding the exposure to the milled material and reducing the risk of accidents too.
The use of a centring auxiliary ring (21) fixed to the reduction gear (19) by means of calibrated screws (24) allows a quick centring of the milling-drum axis with respect to the right-hand side wall (18)
The collecting belt (5) receives the milled material thanks to the loading action of the milling drum (3) when the drum operates on the maximum provided width. When the milling drum (3) works with reduced cutting widths, the milled material is only partially directly discharged onto the collecting belt (5) by the action of the milling drum (3). In this condition the milling drum housing (7) on the left side of the drum tends to be filled with the milled material, that is picked by the collecting belt (5) due to the overflow. However, it will be apparent to those skilled in the art that blades (not represented) could be mounted on the outer surface of the milling drum collar (22), said blades being integral with the milling drum collar itself and thus rotating at the same speed of the milling drum, said blades being suitable to push the milled material toward the collecting belt for facilitating its removal from the inside of the milling drum housing. Alternatively, the external surface of said milling drum collar (22) can be protected by means of a protection tube (not represented), made in long-wearing steel. The rear mouldboard (8) must settle (Fig. 13) to the various milling width, for which reason it is manufactured, according to prior art, in two or more sectors (31, 32). Said sectors are independently operated so that a part of them exactly enters inside the excavation made by the milling drum (3) in order to clean the milled surface and prevent the rearward exit of the milled material from the milling machine, while the remaining part(s) is(are) in contact with the road surface on the left-hand side of the excavation.
The description of this invention has been made with reference to the enclosed figures showing a preferred embodiment of the invention itself, but it is evident that many alterations, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Thus, it should be understood that the invention is not limited by the foregoing description, but embraces all such alterations, modifications and variations in accordance with the scope of the appended claims.

Used nomenclature

With reference to the identification numbers reported in the enclosed figures, the following nomenclature has been used:

1. Chassis
2. Track
3. Milling drum
4. Telescopic columns
5. Collecting belt
6. Loading belt
7. Milling drum housing
8. Rear mouldboard
9a. Right side plate
9b. Left side plate
10. Discharge opening
11. Pressure bar
12. Pulley
13. Reduction gear (traditional solution)
14. Right-hand support
15. Fixing flange of the reduction gear on the milling drum housing (traditional solution)
16. Fixing flange on the milling drum (traditional solution)
17. Fixing flange of the support (traditional solution)
18. Hinged right-hand wall
19. Reduction gear
20. Transmission shaft
21. Auxiliary ring
22. Milling drum collar
23. Hinge
24. Calibrated screws
25. Screws
26. Fixing screws
27. Low friction ring
28. Rotating ring
29. Sealing
30. Bearing of the rotating ring
31. Mouldboard left-hand sector
32. Mouldboard right-hand sector
33. Bearing of the transmission shaft
34. Labyrinth seal
35. Right-hand wall screws
36. Rotating support
37. Grease conduit

Claims

Self-propelled road milling machine including a milling drum housing (7) mounted on the chassis (1) of the machine, said milling drum housing (7) including a first side comprising a power take-off able to transmit the rotational motion from an engine and a second side with an openable hinged wall (18), the second side being the opposite side of said milling drum housing (7) with respect to said first side, inside said milling drum housing (7) being mounted a milling drum (3) selected from a series of milling drums, each of said milling drums (3) being in a single piece and including cutting tools on its external surface and fastening elements radially protruding from its internal surface, wherein the mounting of said milling drum (7) is carried out in an axially sliding way from said second side of the drum housing in order to allow the replacement of said milling drum (3) by means of said openable hinged wall (18), said milling drum (3) being rotated by intermediation of a reduction gear (19) mounted at said second side of the drum housing and a transmission shaft (20) transmitting the rotational motion from said power take-off to said reduction gear (19), said milling drum (3) being supported and centred at the second side of the drum housing by means of said reduction gear (19) which in turn is supported by said openable hinged wall (18) through an auxiliary ring (21) centring the milling drum, said auxiliary ring (21) being fixed by means of screw means (24), characterized in that said milling drum (3) is provided with a hollow milling drum collar (22) constituting an hollow spacer having a length corresponding to the difference between the cutting width of said milling drum and the maximum milling drum cutting width of said road milling machine, said hollow milling drum collar (22) being supported and centred at said first side of the drum housing by means of a rotating support (36) comprising a low friction ring (27) and a rotating ring (28) supported by a bearing (30), wherein
during the insertion and extraction steps of the milling drum, said milling drum collar (22) slides longitudinally over said low friction ring (27) with respect to the axis of said milling drum (3).
Self-propelled road milling machine according to the previous claims characterized in that said bearing (30) is endowed with grease lubricating means, supplied by means of a grease axial-parallel duct (37) from external side.
Self-propelled road milling machine according to the previous claim characterized in that said rotating support (36) comprises a sealing labyrinth (34) discharging the exceeding grease volume.
Self-propelled road milling machine according to any of the previous claims characterized in that, it is structured in such a way that during the milling drum (3) extraction, said reduction gear (19) can be extracted together with said milling drum (3).
Self-propelled road milling machine according to any of the previous claims 1-4 characterised in that said series of milling drums from which said milling drum (3) to be mounted inside said milling drum housing (7) is selected includes milling drums (3) having different overall width.
Self-propelled road milling machine according to claim 1 characterised in that the openable hinged wall (18) on said second side of the drum housing (7) is hinged according to a vertical axis.
Self-propelled road milling machine according to claim 1 characterised in that said milling drum housing (7) is provided with:
- a vertically movable rear mouldboard (8), said mouldboard being provided with scraper tools in the lower edge,

- said rear mouldboard (8) being hinged on an horizontal axis,

- said rear mouldboard (8) including means able to maintain said rear mouldboard (8) in contact with the surface milled with forced or floating action,

- side movable plates (9a, 9b) including means able to maintain said side movable plates (9a, 9b) in contact with the surface milled with forced or floating action.
Self-propelled road milling machine according to any of the previous claims 1-7 characterised in that it includes at least one conveyor belt able to transport the material milled by said milling drum (3) to suitable means for the collection of the milled material, said conveyor belt receiving the milled material flowing from an opening (10) of said milling drum housing (7).
Self-propelled road milling machine according to the previous claim 8 characterised in that it includes a collecting conveyor belt (5) receiving the milled material flowing from said opening (10) of said milling drum housing (7) and a loading conveyor belt (6) able to transport the milled material from said collecting conveyor belt (5) to said suitable means for the collection of the milled material, the part of said collecting conveyor belt (5) close to said milling drum housing (7) being supported by supporting means (11) maintained in contact with the surface to mill.
Self-propelled road milling machine according to any of the previous claims characterised in that it is conceived in such a way that the discharge of the milled material occurs frontally with respect to the advancing direction of the machine.
Method of change of a milling drum in a self-propelled road milling machine conceived according to any of the previous claims characterized in that the change/substitution of the said milling drum (3) consists of the following steps:
- supporting the milling drum (3) by means of milling drum support means

- removing the screws (25) fixing said reduction gear (19)

- removing said calibrated screws (24) fixing said auxiliary ring (21)

- removing wall screws (35) fixing the openable hinged wall (18) to the frame of the drum housing (7)

- extraction of the milling drum (3) together with said reduction gear (19) by pulling back said milling drum support means.

- fitting of a new milling drum (3) together with the reduction gear (19) performing the same operations in reverse order.
Method of change/substitution of the milling drum (3) in a self-propelled road milling machine according to previous claim 11, characterised in that it includes an additional step for the removing of said reduction gear (19) from said milling drum (3) after the extraction of the milling drum (3) together with said reduction gear (19).