Technical Field

[001 ] The invention relates to road milling apparatus and an associated method of road milling.

Background

[002] Road milling involves use of a milling machine or apparatus to smooth out lumps or bumps in the road surface. Such machines typically include a drum with cutting fingers that engage with the ruts, lumps or bumps to cut these to a desired level, typically in line with the surrounding road surface.

[003] One example of a milling machine is disclosed in US8262168. This machine has a main frame with drive tracks and two rotary drums suspended below the main frame of the machine. The two rotary drums are raised and lowered to a cut altitude by hydraulic rams and the machine is carried by and propelled by the drive tracks.

[004] A problem with such machines is that such machines are relatively large and difficult to handle in some situations. Other problems relate to the setting of the cut altitude or depth that results in the cut not matching or following the road profile, especially for smaller patches of road. This results in undesirable transition bumps between the existing road and the milled road.

[005] The invention disclosed herein seeks to overcome one or more of the above identified problems or at least provide a useful alternative.

Summary

[006] In accordance with a first broad aspect there is provided, a road milling apparatus including: a first section having first ground engaging wheels and a first rotatable milling drum extending substantially between and carried by the first ground engaging wheels, and a second section having a second rotatable milling drum substantially parallel to the first rotatable cutting drum, wherein the first and second sections are movably coupled such that the apparatus is moveable between a first milling position in which the first rotatable milling drum and second rotatable milling drum are both engageable with a ground surface, and a second milling position in which first rotatable milling drum is elevated relative to the second rotatable milling drum with the second rotatable milling drum remaining engageable with the ground surface.

[007] In an aspect, the second section includes second ground engaging wheels and the second rotatable drum extends substantially between and is carried by the second ground engaging wheels.

[008] In accordance with a second broad aspect there is provided, a road milling apparatus including: a first section having first ground engaging wheels and a first rotatable milling drum extending substantially between the first ground engaging wheels; and a second section having second ground engaging wheels and a second rotatable milling drum extending substantially between the second ground engaging wheels and being substantially parallel to the first rotatable milling drum; wherein the first and second sections are movably coupled such that the apparatus is moveable between a first milling position in which the first rotatable milling drum and the second rotatable milling drum are engageable with a ground surface, and a second milling position in which the first rotatable milling drum is elevated relative to the second rotatable milling drum with the second rotatable milling drum remaining engageable with the ground surface.

[009] In an aspect, in the first milling position the first rotatable milling drum is closer to a leading milling end of the apparatus relative to the second rotatable milling drum.

[0010] In another aspect, in the second milling position the second rotatable milling drum becomes closer to a leading milling end of the apparatus with the first section elevated above the second section.

[0011] In yet another aspect, the first section includes a forward shroud having opposing sides, a top and a front, and wherein the first ground engaging wheels are located at the opposing sides with the first rotatable milling drum extending substantially between the opposing sides within the forward shroud.

[0012] In yet another aspect, the second section includes a rear shroud having opposing sides, and wherein the rear ground engaging wheels are located at the opposing sides of the rear shroud with the second rotatable milling drum extending substantially between the opposing sides of the rear shroud.

[0013] In yet another aspect, the forward shroud includes an open rear arranged to closably fit with an open front of the rear shroud in the first position.

[0014] In yet another aspect, in the second position the open rear of the forward shroud moves away from the open front of the rear shroud to reveal the second rotatable milling drum.

[0015] In yet another aspect, the first ground engaging wheels have a larger diameter relative to the second ground engaging wheels.

[0016] In yet another aspect, the first ground engaging wheels have a diameter larger, preferably only slightly larger, than a diameter of the first rotatable milling drum.

[0017] In yet another aspect, the first rotatable milling drum has a larger diameter relative to the second rotatable milling drum.

[0018] In yet another aspect, the first rotatable milling drum is a cutting drum with ground engaging projections.

[0019] In yet another aspect, the second rotatable milling drum is a finishing drum being less course relative to the first rotatable milling drum.

[0020] In yet another aspect, the first section and the second section are slidably coupled by a sliding arrangement such that the first section slidably moves at least partially about the second section in the second milling position.

[0021] In yet another aspect, the sliding arrangement includes at least one guide extending from the second section and a follower coupled to the first section such that the follower is movable to travel along the guide between the first and second milling conditions.

[0022] In yet another aspect, the first ground engaging wheels and first rotatable milling drum each have an axis of rotation that are at least one of aligned and parallel.

[0023] In yet another aspect, the first ground engaging wheels and the first rotatable milling drum share a common axle.

[0024] In yet another aspect, the second ground engaging wheels and second rotatable milling drum each have an axis of rotation that are at least one of aligned and parallel.

[0025] In yet another aspect, the second ground engaging wheels and the second rotatable milling drum share a common axle.

[0026] In yet another aspect, the apparatus is fittable with a machine to at least one power and move the apparatus.

[0027] In yet another aspect, the second rotatable milling drum is closest to the machine in at least the first milling position.

[0028] In yet another aspect, the first ground engaging wheels and a first rotatable milling drum are arranged such that the first rotatable milling drum follows a level of the road surface as defined by first ground engaging wheels.

[0029] In yet another aspect, in the first milling position, the moveable coupling between the first and second sections is such that the first and second sections undergo limited relative movement to follow a level of a ground surface.

[0030] In yet another aspect, in the first milling position, the moveable coupling between the first and second sections is locked to inhibit relative movement of the first and second sections.

[0031] In yet another aspect, in the first milling position, the moveable coupling between the first and second sections is such that the first and second sections undergo limited relative movement to follow respective first and second ground engaging wheels as the first and second ground engaging wheels travel over a ground surface. [0032] In yet another aspect, in the first milling position, the moveable coupling between the first and second sections is locked so as to inhibit relative movement of the first and second sections.

[0033] In yet another aspect, at least the first ground engaging wheels are removably replaceable with elongate sleds that extend lengthwise along opposing sides of the apparatus.

[0034] In yet another aspect, the elongate sleds each include a plurality of wheels.

[0035] In yet another aspect, the elongate sleds are arranged to lock the first and second sections together in the first milling position.

[0036] In accordance with a second broad aspect there is provided, a machine including the road milling apparatus as defined above and hereinbelow.

[0037] In accordance with a third broad aspect there is provided, a method for milling a road surface, the method including: moving a milling apparatus over the road surface with a forward milling drum following the path of forward ground engaging wheels located substantially at opposing sides of the forward milling drum; rotating the forward drum to cut the road surface and finishing the cut road surface by rotating a trailing rear drum located rearward of the forward ground engaging wheels.

[0038] In accordance with a fourth broad aspect there is provided, a method for milling a road surface using an apparatus moveable between a first milling position and a second milling position, the method including: in the first milling position, moving the apparatus over the road surface with a first rotatable milling drum following the path of the road surface as defined by first ground engaging wheels located substantially at opposing sides of the first rotatable milling drum and a second rotatable milling drum that trails the first rotatable drum, and in the second milling position, the first rotatable milling drum being elevated relatively above the second rotatable milling drum such that the second rotatable milling drum becomes substantially forward most of the apparatus. [0039] In accordance with a fifth broad aspect there is provided, an apparatus for milling a road surface including: a first section having first ground engaging wheels and a first rotatable milling drum extending substantially between the first ground engaging wheels, and a second section having a second rotatable milling drum substantially parallel to the first rotatable milling drum, wherein the first and second sections are moveably coupled such that the first section is moveable between a first position in which the first ground engaging wheels are engageable with the road surface and a second position in which the first section and first rotatable milling drum are elevated relative to the road surface with the second rotatable milling drum becoming substantially forward most of the apparatus so as to enable milling proximate an edge of the road surface.

[0040] In accordance with a sixth broad aspect there is provided, a road milling apparatus including: a first section having at least one first ground engaging friction reducing element and a first rotatable milling drum; a second section having at least one second ground engaging friction reducing element and a second rotatable milling drum substantially parallel to the first rotatable milling drum; wherein the first and second sections are movably coupled such that the apparatus is moveable between a first milling position in which the first rotatable milling drum and the second rotatable milling drum are engageable with a ground surface, and a second milling position in which the first rotatable milling drum is elevated relative to the second rotatable milling drum with the second rotatable milling drum remaining engageable with the ground surface.

[0041] In accordance with a seventh broad aspect there is provided, a road milling apparatus including: a first section having at least one first ground engaging friction reducing element and a first rotatable milling drum; a second section having at least one second ground engaging friction reducing element and a second rotatable milling drum substantially parallel to the first rotatable milling drum; wherein the first and second sections are movably coupled such that the apparatus is moveable between a first milling position in which the first rotatable milling drum and the second rotatable milling drum are engageable with a ground surface with the first and second sections be substantially locked to inhibit relative movement between first and second rotatable milling drums, a second milling position in which the first rotatable milling drum is elevated relative to the second rotatable milling drum with the second rotatable milling drum remaining engageable with and following the level of the ground surface.

[0042] In accordance with an eighth broad aspect there is provided, a removable road milling apparatus for a machine, the apparatus including: a first section having at least one first ground engaging friction reducing element and a first rotatable milling drum; a second section having at least one second ground engaging friction reducing element and a second rotatable milling drum substantially parallel to the first rotatable milling drum; wherein the first and second sections are movably coupled such that the apparatus is moveable between a first milling position in which the first rotatable milling drum and the second rotatable milling drum are engageable with a ground surface with the first and second sections having at least some relative movement over the ground surface to allow the respective first and second rotatable milling drums to each follow a level of the ground surface, a second milling position in which the first rotatable milling drum is elevated relative to the second rotatable milling drum with the second rotatable milling drum remaining engageable with and following the level of the ground surface.

[0043] In accordance with a ninth broad aspect there is provided, a road milling apparatus including: a first section having first ground engaging wheels and a first rotatable milling drum extending substantially between the first ground engaging wheels, the first ground engaging wheels and the first rotatable milling drum rotating about a common first axis; and a second section having second ground engaging wheels and a second rotatable milling drum extending substantially between the second ground engaging wheels and being substantially parallel to the first rotatable milling drum, the second ground engaging wheels and the second rotatable milling drum rotating about a second common second axis; wherein the first and second sections are movably coupled such that the apparatus is moveable between a first milling position in which the first rotatable milling drum and the second rotatable milling drum are engageable with a ground surface, and a second milling position in which the first rotatable milling drum is elevated relative to the second rotatable milling drum with the second rotatable milling drum remaining engageable with the ground surface. Brief Description of the Figures

[0044] The invention is described, by way of non-limiting example only, by reference to the accompanying figures, in which;

[0045] Figure 1 is a perspective view illustrating a road milling apparatus coupled to a machine in a first position;

[0046] Figure 2 is a perspective part cut-away view illustrating the road milling apparatus;

[0047] Figure 3 is a perspective view illustrating the road milling apparatus coupled to a machine in a second elevated position;

[0048] Figure 4 is a side view illustrating the road milling apparatus in use in the first position;

[0049] Figure 5 is a side view illustrating the road milling apparatus in use in the second elevated position;

[0050] Figure 6 is a front part cut-away view illustrating the road milling apparatus;

[0051] Figure 7 is a detailed front part cut-away view illustrating a wheel and a forward cutting drum of the milling apparatus;

[0052] Figure 8 is a perspective view illustrating a second example of a road milling apparatus coupled to a machine in a first position;

[0053] Figure 9 is a perspective cut away view illustrating the second example of the road milling apparatus coupled to the machine in the first position;

[0054] Figure 10 is a perspective view illustrating the second example of the road milling apparatus coupled to the machine in a second position;

[0055] Figure 11 is a side view illustrating the second example of the road milling apparatus coupled to the machine in the first position;

[0056] Figure 12 is a side view illustrating the second example of the road milling apparatus coupled to the machine in the second position;

[0057] Figure 13 is a perspective view illustrating the second example of the road milling apparatus with a removable guide;

[0058] Figure 14 is a perspective view illustrating the second example of the road milling apparatus showing how the removable guides are fitted to the road milling apparatus;

[0059] Figure 15 is a perspective view illustrating the second example of the road milling apparatus with the removable guides fitted to the road milling apparatus; and

[0060] Figure 16 is a side view illustrating the second example of the road milling apparatus with the removable guides fitted to the road milling apparatus.

Detailed Description

[0061] Referring to Figures 1 to 7 there is shown a first example of a road milling apparatus 10 for removable coupling with a machine 12. The machine 12 may be any suitable machine such as, but not limited to, a skid-steer loader. The road milling apparatus 10 being adapted to cut or mill a road surface. Figures 8 to 15 illustrate a second example of the road milling apparatus 10 which is described below after the description of the first example.

[0062] Turning to initially to Figure 1 to 5, the first example of the apparatus 10 includes a main body 14 having a first section 15 in the form of a first forward shroud 16 movably coupled to a second section 17 in the form of a second rear shroud 18. In this example, the first section 15 and second section 17 are pivotally coupled by a lifting means. However, other movable couplings or lifting arrangements may be used such as a sliding coupling as shown in the second example below or lifting means such as a worm drive. [0063] In this example, the rear shroud 18 is closest to the machine 12, in use. The forward shroud 16 includes first ground engaging friction reducing parts provided here in the form of first forward ground engaging wheels 20 located at sides 22 of the forward shroud 16 and a first or forward rotatable milling drum 24 extending between the sides 22 generally between the forward ground engaging wheels 20. The forward rotatable milling drum 24 may be configured to be a cutting drum.

[0064] The rear shroud 18 includes second friction reducing parts provided here in the form of rear ground engaging wheels 26 located at sides 28 of the rear shroud 18 and a second or rear rotatable milling drum 30 extending between the sides 28 generally between the rear ground engaging wheels 26. The second or rear rotatable milling drum 30 may be a finishing drum arranged to provide a relatively finer cut relative to the first or forward rotatable milling drum 24.

[0065] In this example, the forward shroud 16 and rear shroud 18 are coupled by a hinge 32 that provides a pivotal coupling 33 so as to be moveable between a first milling position as shown, for example, in Figure 4, and a second milling position as shown, for example in Figure 5, in which the forward shroud 16 is moved to elevate the forward rotatable cutting drum 24 above the road surface.

[0066] In the first milling position, the forward rotatable cutting drum 24 is engageable with the road surface to cut the road surface and the rear rotatable milling drum 30 may be a finishing drum to provide a finishing cut trailing the forward rotatable cutting drum 24. Accordingly, the forward shroud 16 and forward rotatable cutting drum 24 are closest toward a leading milling end of the apparatus 10, in that, the forward rotatable cutting drum 24 traverses and cuts the road surface prior to the second rotatable milling drum 30.

[0067] In the second milling position the second rotatable milling drum 30 becomes substantially forward most of the apparatus 10 with the forward shroud 16 elevated above the rear shroud 18. This allows the second rotatable milling drum 30 access to portions or edges of the road surface normally obstructed by the forward shroud 16 and first rotatable milling drum 24. The second rotatable milling drum 30 may now be closest toward a leading milling end of the apparatus 10, in that, the second rotatable milling drum 30 is now the leading cutting drum.

[0068] It is noted that in the second milling position the rear ground engaging wheels 26 support the apparatus 10. However, in some examples, the rear ground engaging wheels 26 could be omitted or replaced with skids. It is also noted that in the second milling position the height and forward/backward position by which the forward shroud 16 or the first rotatable milling drum 24 is moved may vary with the function being that the second rotatable milling drum 30 is able to be moved closer to an edge or divider of a road without being obstructed by the forward shroud 16 or the first rotatable milling drum 24. For example, the lifted height of the first rotatable milling drum 24 may be sufficient to just pass over a gutter or to be above the second rotatable milling drum 30.

[0069] Turning to the structure of the apparatus 10 in more detail and referring more specifically to Figure 2, the forward shroud 16 includes a top 34 and a front 36 that curves from the top 34 to a lower forward edge 38. The rear 40 of the forward shroud 16 is open so as to fittingly meet a corresponding open front 42 of the rear shroud 18. A rear edge 44 of the top 34 supports the hinge 32 coupled to the rear shroud 18 at its forward edge 54. The forward shroud 16 is substantially longer than the rear shroud 18 to laterally space the first rotatable milling drum 24 well forward of the second rotatable milling drum 30.

[0070] The top 34 includes an attachment point 46 for one or more actuators 48 coupled and driven by the machine 12. The one or more actuators 48 are provided in this example as a pair of hydraulic actuators that act to move the forward shroud 16 between the first and second positions in response to operator inputs from the machine 12.

[0071] It is noted that the top 34 may include a grate or openable window (not shown) to provide visibility for the operator in the second elevated position. Each of the first rotatable milling drum 24 and second rotatable milling drum 30 may be powered by respective first and second hydraulic motors, 51, 57 shown only in Figure 4. The first hydraulic motor 51 may be fitted atop the forward shroud 16 and a belt 53 may be coupled to the forward rotatable cutting drum 24 to rotatably drive the forward rotatable cutting drum 24. Similarly, the second hydraulic motor 57 may be fitted atop the rear shroud rear shroud 18 and also includes a belt 59 that rotatably drives the second rotatable milling drum 30. Each of the first and second hydraulic motors, 51, 57 is in fluid communication with a hydraulic line 55 that is connected to a hydraulic power source such as that carried by the machine 12. The machine 12 may have or be configured to operate a hydraulic control system including hydraulic solenoid valves (not shown). For example, the machine 12 may be controlled to operate the pair of hydraulic actuators and rotatable speed of the hydraulic motor 51, 57.

[0072] The rear shroud 18 also includes a top 50 between its opposing sides 28 and a closed rear 52. The rear 52 of the rear shroud 18 may be adapted to couple with the machine 12 in addition to the pair of hydraulic actuators coupled to the forward shroud 16. In some examples, the rear 52 of the rear shroud 18 may be arranged to allow some lateral or axial pivoting to allow the apparatus 10 to be steered or rolled and may include rubber mounts and/or an actuator to facilitate and control movement

[0073] In other examples, the hydraulic actuators may be set with some slack or play to allow the front shroud 16 and rear shroud 18 some relative movement, in use. In still other examples, the hydraulic actuators may be locked out in the first milling position so that the first rotatable milling drum 24 is held against bouncing. Overall, however, apparatus 10 may have some play relative the machine 10 so that each of the

[0074] In this example, the forward ground engaging wheels 20 have a diameter that is slightly larger than the first rotatable milling drum 24. The diameter of the first rotatable milling drum 24, at its maximum, being defined by tips of cutting fingers or projections 56 that extend from the cylindrical body 58 of the first rotatable milling drum 24, as best shown in Figures 6 and 7.

[0075] The axis of rotation of the forward ground engaging wheels 20 and the first rotatable milling drum 24 are generally aligned, and the forward ground engaging wheels 20 and the first rotatable milling drum 24 may share a common axle 25. However, the common axle may be split, of course, via a bearing (not shown) to allow the first rotatable milling drum 24 to rotate independently of the forward ground engaging wheels 20. [0076] This, in essence, allows the first rotatable milling drum 24 to track or follow the road surface which is important to allow transitioning of the cut, in particular, for smaller works and works transverse to roads with recessed tyre tracks.

[0077] The axis of rotation of the rear ground engaging wheels 26 and the second rotatable milling drum 30 may also be generally aligned, and the rear ground engaging wheels 26 and the first rotatable milling drum 30 may also share a common axle 31. This also allows the second rotatable milling drum 30 to track or follow the ground surface. Again, the common axle 31 may, of course, be split by one or more bearings (not shown) to allow the second rotatable milling drum 30 to rotate independently of the rear ground engaging wheels 26.

[0078] The second rotatable milling drum 30 and rear ground engaging wheels 26 and have a similar diameter, that is less than, and preferably about half that of the corresponding forward ground engaging wheels 20 and the first rotatable milling drum 24. The smaller diameter of the rear ground engaging wheels 26 allows the second section 17 to be more sensitive to smaller imperfections in the road surface. The second rotatable milling drum 30 is preferably a finishing drum having disks or the like that are relatively smoother or less course in comparison to the cutting projections 56 of the first rotatable milling drum 30. The disks may be set to be slightly elevated in the first cutting position relative to the tips of cutting fingers or projections 56 as shown in Figure 7.

Second Example

[0079] Referring now to Figures 8 to 12 there is shown a second example of the apparatus 110 in which like sequences of numerals denote like parts (i.e 10, 110 etc). This example shares a similar overall function to the first example, so each similar part is not again described in detail.

[0080] In this second example of the apparatus 110, the movable coupling to elevate and lower the first section 115 relative to the second section 117 is achieved via a sliding arrangement 160 as opposed to pivoting as shown in the first example. Although, both examples achieve a similar function of allowing the first section 115 to be selectively elevated relative to the second section 117. The benefit of the sliding arrangement 160 relates to less potential obstruction of the view of a driver (not shown) of the machine 112 and also the mechanics of lifting the first section 115 that may be relatively heavy.

[0081] Turning now to the second example 110 in more detail, the apparatus 110 again includes a main body 114 having a first section 115 in the form of a forward shroud 116 movably coupled to a second section 117 in the form of a rear shroud 118. In this example, the first section 115 and second section 117 are slidably coupled by the sliding arrangement 160 described in more detail below. The rear shroud 118 is lower most and typically closest to the machine 112 in the first milling position.

[0082] The forward shroud 116 includes first forward ground engaging wheels 120 and a forward rotatable cutting drum 124 (shown in Figure 9) extending between the sides 122 generally between the forward ground engaging wheels 120. In this example, the forward shroud 116 may extend back and at least partially over the rear shroud 118.

[0083] The rear shroud 118 includes second rear ground engaging wheels 126 located at sides 128 of the rear shroud 118 and a rear rotatable finishing drum 130 (shown in Figure 9) extending between the sides 128 generally between the rear ground engaging wheels 126.

[0084] In this example, the forward shroud 116 and rear shroud 118 are coupled by the sliding arrangement 160 so as to be moveable between a first milling position as shown, for example, in Figure 11, and a second milling position as shown, for example in Figure 12, in which the forward shroud 116 is moved to elevate the forward rotatable cutting drum 124 above the road surface. It is noted that in this example the forward shroud 116 does move at least partially rearwardly and over the rear shroud 118 in the second position.

[0085] In the first milling position, the forward rotatable cutting drum 124 is engageable with the road surface to cut the road surface and the rear rotatable milling drum 130 may provide a finishing cut trailing the forward rotatable cutting drum 124, and in the second milling position the second rotatable milling drum 130 becomes substantially forward most of the apparatus 110, relative to the road surface, with the forward shroud 116 elevated above and partly rearward of the rear shroud 118. This allows the second rotatable milling drum 130 access to portions or edges of the road surface normally obstructed by the forward shroud 116 and first rotatable milling drum 124.

[0086] Turning to the structure of the apparatus 110 in more detail and referring more specifically to Figures 9, 10 and 11, the forward shroud 116 includes a top 134 and a front 136 that curves from the top 134 to a lower forward edge 138. The rear 140 of the forward shroud 116 is open so as to fittingly meet a corresponding open front 142 of the rear shroud 118.

[0087] The forward shroud 116 may be longer than the rear shroud 116 to laterally space the first rotatable milling drum 124 well forward of the second rotatable milling drum 130 in the first milling position. The rear shroud 118 also includes an open top 150 between its opposing sides 128 and a closed rear 152. The rear 152 of the rear shroud 118 may be adapted to couple with the machine 112. In some examples, the rear 152 of the rear shroud 118 may be arranged to allow some lateral or axial pivoting to allow the apparatus 110 to be steered or rolled and may include rubber mounts and/or an actuator to facilitate and control movement.

[0088] The sliding arrangement 160 includes a pair of guide rails 162 that extend from supports 164 at the opposing sides 128 of the rear shroud 118 to supports 166 provided on arms 168 of the machine 112. The forward shroud 116 has a pair of followers 170 arranged to slide or travel along the respective guide rails 162 when the forward shroud 116 is moved between the first and second positions.

[0089] The sliding arrangement 160 further includes a pair of actuators 172 (shown best in Figure 8) that are connected between supports 174 of the machine 112 and further supports 176 atop of the forward shroud 116. The pair of actuators 172 are preferably long travel hydraulic actuators. However, it is noted that other forms of actuators (or even a single actuator) may be used such as a worm drive.

[0090] As may be best appreciated from Figure 12, the sliding arrangement 160 allows the forward shroud 116 to be selectively elevated and move relatively backwardly over the rear shroud 118 in the second milling position. Further, in this position, the forward shroud 116 is may be substantially carried by the rear shroud 118 via the rear wheels 126. [0091] The angle of the guide rails 162 may be about 45 degrees from the horizontal, although other angles such as in the range of 15 to 75 degrees could be used. In the second position, it is noted that a forward most surface 159 of the second rotatable milling drum 130 is about in line with the lower forward edge 138 of the forward shroud 116.

[0092] It is noted that in some examples the first milling position, the sliding arrangement 160 may allow some play or travel between the first and second sections 115, 117 which allows these sections first and second sections 115, 117 to individually follow the ground surface across which the apparatus 110 is moved. However, in other examples, the sliding arrangement 160 may be arranged to lock out in the first milling position so that the first and second sections 115, 117 move as a substantially single unit and this may inhibit bouncing of the forward rotatable cutting drum 24 which may need substantially downward pressure to cut the road surface.

[0093] Like the first example, each of the first rotatable milling drum 124 and second rotatable milling drum 130 may be powered by respective first and second hydraulic motors, 51, 57 shown only in Figures 11 and 12. The first hydraulic motor 151 may be fitted atop the forward shroud 116 and a belt 153 may be coupled to the forward rotatable cutting drum 124 to rotatably drive the forward rotatable cutting drum 124.

[0094] The second hydraulic motor 157 may be fitted atop or within the rear shroud 118 and also includes a belt 161 that rotatably drives the second rotatable milling drum 130. In this example, the second hydraulic motor 157 needs to be positioned to remain proximate the second rotatable milling drum 130 and may be coupled to the rear shroud 18 just below or within a cut out (not shown) of the forward shroud 116.

[0095] Each of the first and second hydraulic motors, 151, 157 is in fluid communication with one or more hydraulic lines 155 that is connected to a hydraulic power source such as that carried by the machine 112. In this example, two hydraulic lines 155 are required to allow the movement of the first and second hydraulic motors, 151, 157 when the forward shroud 116 is elevated in the second milling position. [0096] The machine 112 may have or be configured to operate a hydraulic control system including hydraulic solenoid valves and a manifold (not shown). For example, the machine 112 may be controlled to operate the pair of hydraulic actuators 112 and rotatable speed of any hydraulic motors 151, 157. For example, additional hydraulic controls (not shown) may be fitted to the machine 112 which control hydraulic pressure to the pair of hydraulic actuators 112 and any hydraulic motors that rotate the drums 124, 130. A user may then selectively move the apparatus 110 between the first and second cutting positions and also control the rotation speed of the drums 124, 130.

[0097] Like the first example, in this second example, the forward ground engaging wheels 120 have a diameter that is slightly larger than the first rotatable milling drum 124. The diameter of the first rotatable milling drum 124, at its maximum, being defined by tips of cutting fingers or projections 156 that extend from the cylindrical body 158 of the first rotatable milling drum 124, as best shown in Figure 9.

[0098] The axis of rotation of the forward ground engaging wheels 120 and the first rotatable milling drum 124 are generally aligned, or may be parallel, and the forward ground engaging wheels 120 and the first rotatable milling drum 124 may share a common axle 125. The common axle 125 may, of course, be split by one or more bearings (not shown) to allow the first rotatable milling drum 124 to rotate independently of the forward ground engaging wheels 120.

[0099] This, in essence, allows the first rotatable milling drum 124 to track or follow the road surface which may be important to allow transitioning of the cut, in particular, for smaller works and works transverse to roads with recessed tyre tracks.

[00100] The axis of rotation of the rear ground engaging wheels 126 and the second rotatable milling drum 130 may also be generally aligned, and the rear ground engaging wheels 126 and the second rotatable milling drum 130 may also share a common axle 131. This also allows the second rotatable milling drum 130 to track or follow the ground surface. Again, the common axle 131 may, of course, be split by one or more bearings (not shown) to allow the second rotatable milling drum 130 to rotate independently of the rear ground engaging wheels 126. [00101] Like the first example, the second rotatable milling drum 130 and rear ground engaging wheels 126 and have a similar diameter, that is less than, and preferably about half that of the corresponding forward ground engaging wheels 120 and the first rotatable milling drum 124. The smaller diameter of the rear ground engaging wheels 126 allows the second section 117 to be more sensitive to smaller imperfections in the road surface. The second rotatable milling drum 130 is preferably a finishing drum having disks or the like that are relatively smoother or less course in comparison to the cutting projections 156 of the first rotatable milling drum 130. The disks may be set to be slightly elevated in the first cutting position relative to the tips of cutting fingers or projections 156 as shown in Figure 9.

Attachments

[00102] Referring to Figures 13 to 15, there is shown levelling attachment 180 that may couple with either of the first or second examples of the apparatus 10, 110, although in this example the levelling attachment 180 is shown as being fitted to the second example of the apparatus 110. The levelling attachment 180 includes a pair of elongate sleds 182 each having a plurality of wheels 184 and sled couplings 186. The apparatus 10, 110 may be modified to attach with the pair of elongate sleds 182 by removal of the wheels 120, 126 and then coupling of the sled couplings 186 to the respective axles 125, 131.

[00103] The levelling attachment 180, namely the pair of elongate sleds 182, allow the front and rear shrouds 116, 118 to be connected together, thereby moving as a single unit, and track or roll along a road surface in accordance with the greater length of the pair of elongate sleds 182. This allows the apparatus 10 to be modified to be used in further applications in which more gradual levelling such as lengthwise along a road is required and the cut is about the average of the first and second milling drums 124, 130.

Method of Use & Advantages

[00104] Turning now to a method of use, the apparatus 10, 100 may find various applications. However, the apparatus 10, 100 is particularly well suited to smaller works such as cutting and smoothing corrugations on a small patch of road, for example, a 15 metre by 15 metre patch of road.

[00105] Such works may be on an existing road that has well-worn parallel tyre indents and the apparatus 10, 110 may be operated in the first cutting position transverse to the parallel tyre indents with the forward ground engaging wheels 20, 120 tracking and travelling over the parallel tyre indents with the forward rotatable cutting drum 24, 124 following the forward ground engaging wheels 20, 120. The second rotatable milling drum 30, 130 follows the forward rotatable cutting drum 24, 124 to smooth out and finish the cut road surface.

[00106] In both examples of the apparatus 10, 110, the moveable coupling of the first section 15, 115 and second section 17, 117 may allow some limited movement or travel between the first section 15, 115 and second section 17, 117 such as limited vertical travel. This limited movement or travel allows each section to individually track the ground surface across which the apparatus 10, 110 travels in use and thereby allow the forward rotatable milling drum 24, 124 and rear rotatable milling drum 30, 130 more closely follow the level of the road surface appropriate to the relative size of the milling drum and improve the milling or cutting.

[00107] Further, it is noted that because the axis of rotation of the forward ground engaging wheels 20, 120 and the forward rotatable cutting drum 24, 124 are either aligned or parallel, the forward rotatable cutting drum 24, 124 generally follows the path or level of the road surface as defined by the forward ground engaging wheels 20, 120.

[00108] At edges of the road surface, there are sometimes median strips, liners or other obstacles that are not required to be cut. Accordingly, toward the road edges the apparatus 10, 110 may be moved to the second elevated position with the forward rotatable cutting drum 24, 124 elevated above the road surface. This allows the second rotatable milling drum 30, 130 to be moved close to the road edges and finish the edges that would otherwise be missed. [00109] The apparatus 10, 110 may also be used in the second elevated position to finish the road surface more generally and also for minor bumps and corrugations that may not require course cutting.

[00110] In some applications, such as works to grind a lengthwise section of road, the levelling attachment 180 may be fitted as described above which allows the forward cutting drum 24, 124 and rear cutting drum 30, 130 to move as a single unit, being locked together, and track more gradual changes or inclines in the road surface.

[00111] It is noted that whilst in this example the apparatus 10, 110 is shown as a removable attachment for a machine 12, 112, in other examples, the apparatus 10, 112 and machine 12 may be a single integral unit. That, the apparatus and machine, are produced and used as a single machine.

[00112] Advantageously, there has been described a road milling apparatus that is preferably releasably attachable to a machine. The road milling apparatus includes a forward larger milling drum and a smaller rear or trailing milling drum. The forward wheels may be on about the same axis of rotation as the forward larger milling drum and have a similar diameter to allow the forward milling drum to track the road surface over which it is travelling. This allows the forward milling drum to track the surface, in particular smaller bumps and undulations, and provide a smooth cut and transition between different levels in the road.

[00113] Similarly, the rear wheels may be on the same axis of rotation as the rear smaller milling drum and have a similar diameter to allow the rear milling drum to track the road surface, in particular, in the second milling position when the forward milling drum is elevated thus allowing the rear milling drum to follow smaller level changes or bumps in the road surface in comparison to the forward milling drum and thereby provide a smother finishing cut.

[00114] Further advantageously, in the second milling position, the smaller milling drum, that is preferably a finer finishing drum, may be moved proximate an edge of a road over which the forward larger milling drum has passed and thereby allowing the apparatus to finish surfaces closer to the edge of the road which is particularly advantageous when milling transverse to a road up against a gutter or medium strip barrier.

[00115] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[00116] The reference in this specification to any known matter or any prior publication is not, and should not be taken to be, an acknowledgment or admission or suggestion that the known matter or prior art publication forms part of the common general knowledge in the field to which this specification relates.

[00117] While specific examples of the invention have been described, it will be understood that the invention extends to alternative combinations of the features disclosed or evident from the disclosure provided herein.

[00118] Many and various modifications will be apparent to those skilled in the art without departing from the scope of the invention disclosed or evident from the disclosure provided herein.