Apparatus for removing a surface layer from the ground

Abstract

 Apparatus is described for removing a hard surface layer from the ground, for example from the road comprising a vehicle (20) having support means (24) mounted on a frame (22) of the vehicle (20), a rotary cutting device (32) carried by the support means (24) and moving means, conveniently provided by hydraulic rams, for urging a cutter (38) of the cutting device (32) into and out of operative engagement with a surface (18) to be removed on which the vehicle (20) is standing, means is also provided for moving the cutting device (32) in engagement with the surface (18) relative to frame (22) of the vehicle (20) along the surface (18) to remove the surface layer. Apparatus may be use in road planing or in digging a trench in which latter case a digging device is also mounted on the frame (22) of the vehicle (20) to dig out the remainder of the material from the trench.

Description

[0001] This invention relates to apparatus for removing a surface layer from the ground and is especially concerned with apparatus for removing the surface layer from ground having a hard surface layer, for example roads having a hard surface layer of bituminous material or concrete which may commonly be between one and two feet (about 30 and 60 cms) thick.

[0002] It may be required to remove the whole of the surface layer, for example when forming a trench in roadways or other site areas or to remove part of the thickness of the hard surface layer, for example when resurfacing a road. In resurfacing a road it has been proposed to use a rotating milling cutter mounted within the wheelbase or tracks of a vehicle which uses traction effort from the wheels or tracks to propel the vehicle along the surface being milled to mill it to whatever depth is required. In most cases the larger machines (300-750 HP M/C) use tracks because they are able to give more tractive effort and the frictional resistance between the tracks and road surface is high. In the case of small machines (50-200 HP) wheels are usually employed which in wet conditions and on gradients are prone to slip as they force the milling cutter into its work - usually the depth of cut taken has to be reduced in these circumstances necessitating 2 or more passes.

[0003] The milling cutter rotates about a horizontal axis, where the depth can be varied but considerable manouvering of the vehicle may be required to cut round metal manhole covers, or in heavily built up areas.

[0004] In excavating trenches, the hard surface layer has commonly been removed by using pneumatic or hydraulic percussive tools followed by digging the softer material beneath the hard surface layer to form the trench. It has also been proposed to use larger so-called "back-acting" diggers to remove the hard surface layer as well as to dig the softer material but this technique is destructive of the machine and a digging bucket is commonly replaced by a large hydraulic percussive pick to break up the hard surface layer before removing it using a digger. Commonly two such back-acting machines are used, the first with a hydraulic pick to remove the hard surface layer followed by a second machine with a digging bucket to remove the spoil and dig away the softer material to the required depth for the trench.

[0005] Heretofore known machines for removing a hard surface layer, for example part of the surface of a road, have been cumbersome and expensive where tracked vehicles are used and inefficient where smaller vehicles used because of the slipping of wheels as the cutter is moved along its cutting path by movement of the whole apparatus; also, for best effects, expensive load control systems for wheels or tracks are required. When digging trenches two machines have heretofore been required: apparatus in accordance with the invention may remove the need for two separate machines and the attendant operatives.

[0006] In one aspect the invention provides apparatus for removing a surface layer from the ground comprising a vehicle having support means mounted on a frame of the vehicle, a rotary cutting device carried by the support means, and moving means for urging the device into and out of operative engagement with the surface layer of a road on which the vehicle is standing and for moving the device in engagement with the surface layer relative to the frame of the vehicle along the surface layer of the road whereby to remove the surface layer.

[0007] Referring to the drawings:-

Figure 1 is a side view of first apparatus embodying the invention, suitable for use in road planing;

Figure 2 is a plan view of the apparatus shown in Figure 1;

Figure 3 is a plan view similar to Figure 2 but showing a cutter in different operative position;

Figure 4 is a plan view of a second apparatus embodying the invention, suitable for use in excavating trenches in ground having a hard surface layer;

Figure 5 is a view in side elevation of the apparatus shown in Figure 4;

Figure 6 is a side view of a road planer of previously known construction; and

Figure 7 is a plan view of the road planer shown in Figure 6.

[0008] In the drawings like reference numbers indicate like parts.

[0009] As can be seen by viewing Figures 6 and 7, one existing road planer comprises a vehicle 20 movable on tracks 50 and provided with a rotary cutter 39 mounted between front and rear ones of the tracks and extending across the width of the planer. In use, the planer shown in Figures 6 and 7 is moved along the surface to be planed with its cutter 39 in engagement with the surface and rotating. By movement of the vehicle 20 along the surface the cutter is traversed along the surface and the cutter 39 removes a surface layer of the road or other surface being planed. In order to control this operation, expensive load control systems for the tracks are necessary to ensure that the cutter 39 is traversed with the necessary speed and control.

[0010] Figures 1 to 3 show a first apparatus embodying the invention suitable for use in planing the surfaces of roads, for example. The first illustrative apparatus comprises a vehicle 20 having wheels 40 (although it may if desired instead be provided with suitable tracks) by which the vehicle 20 is moved along the surface to be planed to a desired operating position.

[0011] The vehicle 20 of the first illustrative apparatus has a frame 22 on which is mounted support means 24 for a cutting device 32. The support means 24 of the first illustrative apparatus comprises a frame 26 provided, at its extremity remote from its attachment to the vehicle frame 22, with support legs 30. The vehicle 20 is also provided with support legs 28 secured to the vehicle frame 22 remote from the support frame 26. The legs 28, 30 are provided with hydraulic rams (not shown) conveniently operated from the power supply of the vehicle 20 by which ground-engaging pads 29, 31 may be lowered into firm engagement with the surface 18 of ground to be operated upon, for example the hard surface layer of a road. The ground-engaging pads 29, 31 may likewise be retracted by the hydraulic rams away from the surface 18 when the vehicle 20 is to be moved on its wheels.

[0012] In the operation of the first illustrative apparatus, the hydraulic rams urge the ground-engaging pads 29, 31 into engagement with the ground with sufficient force to lift the wheels 40 from the ground so that the whole weight of the first illustrative apparatus is placed on the pads 29, 31. The pads 29, 31 are provided with a series of spikes which penetrate into the hard surface 18 (of tarmacadam, concrete or the like) and act as dowels to maintain the first illustrative apparatus in position over the portion of the surface 18 to be operated upon. As the whole of the weight of the apparatus is dowelled to be surface 18, reaction from the cutting device 32 as it carries out a milling or planing operation on the surface 18 is firmly taken. If the spiked pads 29, 31 prove to be insufficient to retain the apparatus in position adequately, additional dowels (not shown) carried by the frames 22, 26 may be inserted into holes drilled in the surface 18 adjacent each pad 29, 31.

[0013] The support means 24 of the first illustrative apparatus further comprises a carriage 34 by which the cutting device 32 is carried. The carriage 34 is mounted for movement in the direction indicated by the arrows A along the frame 26. A cutter housing 36 is mounted on the carriage 34 for movement transversely of the frame 26 in the direction indicated by the arrows B in Figures 1 to 3 of the drawings. The cutter housing 36 may also be rotated about an axis Y perpendicular to the plane of the frame 26 and generally perpendicular to the surface 18 to be operated upon. A suitable cutter, for example a rotating milling cutter 38, is mounted for rotation about an axis X parallel with the plane of the frame 26.

[0014] As can be seen from Figures 2 and 3 the cutter housing 36 may be pivoted about the axis Y to move the cutter 38 as indicated by the arrows C from a position (shown in Figure 2) in which its axis of rotation X extends transversely of the frame 26 to a position in which it is shown in Figure 3 where its axis X of rotation extends generally lengthwise of the frame 26. The axis of rotation X lies generally parallel with the surface 18.

[0015] The cutter 38 is intended to rotate as indicated by the arrow D about its axis X.

[0016] In the use of the first illustrative apparatus, the vehicle 20 is driven to an appropriate site and positioned to position the frame 26 over a portion of the surface 18 which it is wished to remove. The hydraulic rams are then operated to jack the vehicle up on its legs 28, 30 as shown in Figure 1 and the cutter 38 is set in operation. The cutter 38 is then lowered in the direction indicated by the arrows E into operative engagement with the surface 18 (as indicated in Figure 1) for example by means of a suitable hydraulic ram (not shown) and then moved lengthwise of the frame 26 as indicated by the arrows A to remove the portion of the surface 18 which is to be removed. The cutter may also be traversed in the direction of the arrow B to change its operative position within the frame 26 and to mill a series of parallel lengthwise strips beneath the position of the frame 26. Furthermore, should a manhole cover or other obstruction be present in the region to be milled, the cutter may be rotated as indicated by the arrows C to the position in which it is shown in Figure 3 of the drawings and moved in the direction of arrows B to operate transversely of the frame 26. When the material has been moved from the surface 18 as required, the pads 29, 31 are retracted by the rams and the wheels 40 thus lowered into engagement with the surface so that the vehicle 20 can be driven to a further location in which it is to be operated. The sequence is repeated until the whole area to be treated has been operated on.

[0017] The construction of the first illustrative apparatus is relatively simple and cheap and does not require any expensive system of load control for wheels etc. The cutting device 32 can be traversed both lengthwise and transversely of the frame 26 by simple hydraulic rams (not shown). The first illustrative apparatus may be of substantial dimensions. For example the cutting device may be moved transversely of the frame 26 through a distance of between 1.2 and 2.2 metres allowing the apparatus to operate around obstructions without resorting to secondary operations for example the use of pneumatic picks or the like.

[0018] The depth of cut of the cutter may also be varied as required.

[0019] As the illustrative apparatus is stationary when in operation, only the cutting device 32 moving, it is only necessary to provide protection, for example in the form of rails (not shown) to prevent animals or children becoming enmeshed in the cutter. The protective means for the cutting device 32 is suitably designed so that the operator can see the position of the cutter 38 itself and thus accurately control its position when milling round obstructions. The illustrative apparatus may, if desired, be provided with a radio control system for controlling the movement of the cutter 38 so that the operator is able to closely observe the operation of the cutter whilst controlling it.

[0020] Conveniently the first illustrative apparatus comprises a system (not shown) for removing debris and dust from the region of the cutter 38. A suitable system can comprise pneumatic means for removing debris and dust, the pneumatic means transferring debris etc. to a further conveyor system or to an auger system by which it is transferred into a bunker which retains dust and coarse debris but from which air is vented through a filter system. Conveniently the bunker is mounted on the vehicle 20 and means is provided for tipping it into a lorry to empty the bunker as required. Suitably the capacity of the bunker is sufficient to hold material milled from a surface in thirty to forty minutes of continuous operation.

[0021] The first illustrative apparatus is especially suitable for use in built-up areas as it is able to work with less movement of the whole vehicle relative to the road surface than the heretofore known systems of road planing. Furthermore, the first illustrative apparatus is relatively simple, cheap and efficient by comparison with some known apparatus.

[0022] The second illustrative apparatus is suitable for use in excavating trenches. This second apparatus comprises a vehicle 20 having a vehicle frame 22, support means 24 mounted on the frame 22 of the vehicle 20, the support means 24 carrying a rotary cutting device 32, being provided with moving means for urging the device 32 into and out of operative engagement with the surface 18 of a road on which the vehicle 20 is standing and for moving the device 32, in the direction of the arrows A, in engagement with the surface layer 18 relative to the body of the vehicle 20 along the surface 18 whereby to remove the surface layer. The support means 24 of the second illustrative apparatus comprises an articulated support arm 44 pivotally mounted on the frame 22 of the vehicle 20. At an outer extremity of the articulated support arm 44 a support frame 26 is mounted. The support frame 26 is provided at its four corners with legs 42. Cutting device 32 comprises a cutter housing 36 mounted on the frame 26 for movement lengthwise of the frame. A suitable rotary cutter 38, for example a rotating milling cutter, is mounted for rotation in the housing 36 about an axis X extending transversely of the frame 26 generally parallel with the frame and with the surface 18.

[0023] The articulated arm 44 may be operated by hydraulic rams (not shown) in known manner to lower the frame 26 towards a surface 18 to be operated upon until the legs 42 engage the surface 18 and thereafter to urge the legs 42 (which may be provided with spikes to penetrate the surface 18, as pads 29, 31) firmly into engagement with the surface 18. When in this position, the frame 26 extends generally parallel with the surface 18. If desired the legs 42 may be provided with means for adjusting their height (not shown), conveniently hydraulic rams.

[0024] The second apparatus also comprises legs 28 mounted on the frame 22 at a position remote from the support frame 26. The legs 28 are provided with hydraulic rams (not shown) by which ground-engaging pads (not shown) of the legs 28 may be urged into engagement with the surface 18. By this means and by the arm 44, a substantial amount of the weight of the illustrative apparatus may be supported by the legs 42 and the legs 28 thereby maintaining the apparatus in position on the surface to be operated upon.

[0025] The illustrative apparatus further comprises a second articulated arm 46 mounted on the vehicle frame 22 suitably mounted on the back gate of a back acting vehicle 20 in known manner. The second articulated arm 46 has, at its outer extremity, a digging device 48 which may be operated by the operator of the vehicle 20. If desired, the articulated arm 46 may be mounted on a slide (not shown) by which the arm may be moved transversely of the vehicle. If desired, the frame 26 may be mounted for movement transversely of the vehicle 20 or, alternatively, the cutter housing 36 may be mounted for movement transversely of the frame 26 in a manner similar to that described above with reference to the first illustrative apparatus, although in excavating trenches, provision for such transverse movement will not normally be necessary.

[0026] In the use of the second illustrative apparatus, the vehicle 20 is first driven to the position at which it is required to excavate a trench with both articulated arms 44, 46 in raised positions. The articulated arm 44 is then operated to lower the legs 42 into engagement with the surface 18 in a position where the surface is to be cut, with the cutter 38 or the cutting device rotating, the downward motion of the arm 44 urging the cutting device 38 into the hard surface layer to remove an initial portion of the surface layer. When the frame 26 is in the required position, the legs 28 are also urged into engagement with the surface 18 so that the apparatus is substantially supported by the legs 42, 28. The milling cutter 38 is then moved lengthwise of the frame by hydraulic rams or any other suitable moving means (not shown) in the direction of the arrows A to remove the hard surface layer. The extent to which the cutter 38 is forced into the surface 18 is sufficient to remove the whole of the surface layer at the region where the trench is to be excavated. The cutter 38 may be forced into the surface layer using a hydraulic ram mounted on the frame 26 to force the housing 36 downwardly, or if the legs 42 are of adjustable height, by using controlled retraction of the legs 42 and suitable downward force applied by the arm 44. After cutting the initial portion of the trench in this way, the vehicle 20 is moved, having first lifted the legs 28 and raised the arm 44 and the frame 26 is repositioned with the cutter 38 at a rear end portion of the frame 26 adjacent the vehicle frame 22 and in the hole which had previously been cut by the first operation of the cutter 38: the legs 28 are then again lowered and the cutter traversed in the direction of the arrow A along the frame 26 to the far end, cutting a further length of the hard surface layer to define the trench. Further successive cuts of the hard surface layer are made in this fashion. The wheels 40 of the vehicle 20 will suitably straddle the region of the surface 18 which has been removed and after a sufficient length of the hard surface has been removed, the partially excavated trench will be revealed at the rear of the vehicle. The digging device 48, may then be operated to remove the softer material beneath the hard surface layer and to dig out the trench, the operator alternating between removal of a further amount of the hard surface layer using the cutting device and excavating of an equal length of softer material at the rear of the vehicle.

[0027] In the use of the second illustrative apparatus, the rotary cutting device 32 is lowered to urge the cutter 38 through the hard surface layer and the cutter 38 moves lengthwise of the support frame 26: this initial sumping cut is sufficient to remove the hard surface material and may need to be of a depth of between 0.3 and 0.6 metres for example.

[0028] Modified trenching machines otherwise generally similar to the second illustrative apparatus may have both the cutter device 32 and the digging device 48 mounted at the same end portion of the vehicle frame 22 on a transverse slide means, if desired. The cutting device or the digging device, as required may be pushed e.g. by a hydraulic ram along the slide to a central operating position, the one of the devices not in use being parked at a remote end of the slide out of the way. In this type of machine, with the cutting device 32 and the digging device 48 mounted at the same end of the vehicle, the hard surface layer is first cut away with the cutting device in the central operative position and the cutting device is then traversed along the slide from the central position to an out of the way position being replaced by the digging device 48 by which soft material is excavated from the region where the hard surface layer has been removed by the operation of the cutting device. After removal of the soft material, the apparatus is moved on its wheels or tracks to the next operating position to dig out the next length of the trench to be operated upon.

[0029] In the second illustrative apparatus or the modification thereof just mentioned, a single apparatus can be used to excavate a trench through ground having a hard surface layer with a softer underlayer, for example a road. The operation can be carried more efficiently in this way.

[0030] If desired, part of the trench may first be marked out by using a pair of high speed diamond saws to cut slots defining opposite sides of the trench, the cutter 38 operating between these slots to remove the remainder of the hard surface layer between the slots. In this way sharply defined sides are provided to the trench and the minimum of material is removed. Conveniently the high speed diamond saws may also be mounted on the vehicle frame conveniently being movable along the support frame 26.

[0031] In both versions of the apparatus the operative position of the cutting device is external lengthwise of the wheel base of the vehicle, i.e. forwardly and rearwardly of the vehicle 20.

Claims

1. Apparatus for removing a surface layer from the ground comprising a vehicle movable on ground engaging tracks or wheels and provided with a rotary cutter extending across the width of the vehicle, characterised in that the vehicle (20) having a frame (22), support means (24) mounted on the vehicle frame, the support means including a support frame (26) which carries the rotary cutting device (32), a plurality of legs (30, 28) mounted on the support frame (26) and the vehicle frame (22) respectively, the legs being arranged to be urged in the operation of the apparatus into engagement with the ground whereby to take substantially the whole weight of the apparatus from its ground-engaging tracks or wheels (40) with the support frame (26) generally parallel with the surface layer, and moving means for moving the cutting device (32) in engagement with the surface layer (18) relative to the support frame (26) along the surface layer whereby to remove the surface layer.

2. Apparatus according to Claim 1 characterised in that the plurality of legs (30, 28) are constructed and arranged to lift the whole vehicle.

3. Apparatus according to Claims 1 or 2 characterised in that the plurality of legs (28, 30) each has a ground-­engaging portion (29, 31) and drive means for driving the ground-engaging portion against the ground.

4. Apparatus according to Claim 3 characterised in that said drive means includes a hydraulic ram.

5. Apparatus according to Claims 3 or 4 characterised in that the ground engaging portions (29, 31) are provided with a series of spikes arranged to penetrate the ground whereby to maintain the vehicle in position.

6. Apparatus according to any one of Claims 1 to 5 characterised in that dowels are attached to the frame and arranged to be inserted into the ground adjacent the legs whereby to assist in maintaining the vehicle in position.

7. Apparatus according to any one of the preceding claims characterised in that first transport means (34) is provided for moving the cutting device (32) lengthwise of said support frame (26) to effect removal of said portion.

8. Apparatus according to Claim 7 characterised in that second transport means (36) is provided for moving the cutting device (32) transversely of said support frame (26).

9. Apparatus according to Claim 7 or 8 characterised in that a cutter (38) of the cutting device (32) is mounted for rotation about an axis of rotation generally parallel with the plane of the support frame (26).

10. Apparatus according to Claim 9 wherein the cutting device (32) is mounted for pivotal movement about an axis generally perpendicular to the plane of the support frame (26) whereby the cutter (38) may be positioned to operate with its axis of rotation extending generally lengthwise of the support frame (26) or generally transversely of the support frame (26).

11. Apparatus according to any one of Claims 7 to 10 wherein the support frame (26) is carried by a lifting arm (44) mounted on the vehicle frame (22) and comprises a plurality of legs (42) arranged to be urged into engagement with the ground whereby to locate the frame 26 generally parallel with said surface layer(18).

12. Apparatus according to any one of the preceding claims characterised in that digging means (48) is also mounted on the vehicle frame (22).

13. Apparatus according to any one of the preceding claims for digging trenches characterised in that a first cutting device comprising a pair of high speed diamond saws arranged to cut spaced slots along the surface layer defining edges of the trench and a second cutting device comprising a milling cutter arranged to remove the material of the surface layer between the slots.

14. Apparatus according to any one of claims 1 to 13 characterised in that in the operative position of the cutting device the cutter is external in a lengthwise direction of the wheel base of the vehicle.

15. A method of removing a hard surface layer from the ground characterised in that said method comprises positioning a vehicle (20) having a frame (26) mounting a cutting device (32) adjacent a portion of a surface layer (18) to be removed, moving the cutting device (32) into operative engagement with said portion of the surface layer and moving the cutting device (32) relative to the frame (26) and over said portion whereby to remove said portion of the surface layer.

16. A method of excavating a trench in ground having a hard surface layer characterised in that said method comprises positioning a vehicle (20) having a frame (26) mounting a cutting device (32) adjacent a portion of a surface (18) of ground in which a trench is to be excavated, moving the cutting device (32) into operative engagement with said portion of the surface layer (18) and moving the cutting device relative to the frame (26) and over said portion whereby to remove said portion of the surface layer (18) and excavating material from the region from which the surface layer has been removed.

Drawing