Improvements relating to road working apparatus

Abstract

 The invention provides a road working vehicle (10) such as a skid steer vehicle or small excavator having attached thereto, preferably in place of the bucket of the excavator a road working head (30) comprising a compaction roller (44) which is adapted to roll on the road material to be compacted, for example in a trench, and the head is adapted to castor about an upright axis (42) so that the roller can automatically follow any wavyness in the sides of the trench in which the roller operates. Preferably the roller is of substantial diameter e.g. in the order of 1500 mm, and is made up of a plurality of sections so that sections can be removed when the roller is required to operate in a narrower trench. There may also be a vibrator for vibrating the roller as it works.

Description

[0001] The present invention relates to road working apparatus, and in particular concerns a vehicle attachment or accessory, the function of which is to perform a working operation on a road surface or a road sub-surface. The working operation in one aspect of the invention can be any of several including road surface slitting, road surface planing, road surface rolling and road surface and/or sub-surface compacting and any of various working tools or components may be used in connection with the performing of the function. The attachment or accessory may in fact be arranged to perform several of the said functions simultaneously. For example a road surface or sub-surface may be rolled and compacted simultaneously. In a second aspect of the invention, the tool is for compacting the road filling or surfacing materials.

[0002] The accessory or attachment according to both aspects of the invention is attached to, or for attachment to, a vehicle so that it will overhang an extremity such as an end or side of the vehicle. In the preferred embodiment the attachment overhangs the front of the vehicle and is connected to the vehicle by means of a support arm or support arms which may be a component or components with which the vehicle is already provided, or the arm or arms may form part of the attachment or accessory.

[0003] The invention in the first aspect resides in that the attachment is coupled to the vehicle so that it can turn about a castoring axis so that when in use the vehicle is steered from straight line movement, the working tool or member can change its angular relationship relative to the ground by virtue of castoring about said axis.

[0004] In the preferred case, the vehicle may be a vehicle which has low speed transmission such as an asphalt paver, or a vehicle of the popular skid steer type, a small tracked excavator, which is steered by differentially braking and/or driving ground engaging driving members such as wheels, rollers or tracks, at opposite sides of the vehicle, or a tractor back hoe loader. Driving of the wheels, rollers or tracks in opposite direction can effect steering of the vehicle about an axis within the confines of the sides and ends of the vehicle and a minimum steering radius can be achieved. The castoring of the working tool or component relative to the vehicle, enables the tool to pivot about the castoring axis, and to follow a curved roadworking path.

[0005] In the utilisation of the invention, it is preferred that the front end of the vehicle should be capable of being jacked clear of the ground by thrusting the working tool into firm engagement with the road surface, using the support arm or support arms. The support points for the assembly therefore become the working tool on the one hand, and the rear wheels or rear portions of the tracks of the vehicle. This has the dramatic effect of moving the effective steering axis of the vehicle towards the rear of same and typically between the rear wheels or the rear portions of the tracks. Steering can therefore effect virtual lateral sideways movement of the tool for moving the tool rapidly from side to side over the surface to be treated, or from side to side of a trench in which the tool is working.

[0006] The tool as stated above can be used for any other variety of roadworking purposes including trenching, slitting, compacting and rolling, and preferably the attachment includes vibration means for vibration of the tool or ground working component in order to enhance compaction, cutting and/or planing.

[0007] The castorable tool is preferably supported by an arm or a pair of arms which conventionally supports a digger bucket of an excavator or which supports a loader bucket of a skid steer vehicle, said loader arm or arms being swingable in vertical planes by means of hydraulic ram devices. With this arrangement, the loader arms can be lowered in order to lower the road working tool onto the road surface under the action of the jacking devices which will in fact cause the front end of the vehicle to be raised clear of the ground so that the weight of the vehicle (which is substantial in the case of a skid loader) can at least partially be transferred via the loader arms onto the road working tool in order to provide better working conditions when the tool performs its roadworking function on the road surface.

[0008] The invention provides roadworking equipment wherein the roadworking tool or component can follow curved paths readily by being castored relative to the vehicle on which the equipment is mounted, even though the vehicle may have to follow a sharply curved path. By manipulating the steering, the tool or component can be moved at right angles to the fore and aft direction of the vehicle.

[0009] The working tool may be mounted on suitable vibration isolation mountings of rubber or the like to isolate working tool vibrations from the vehicle. The said mountings may be of such yieldability to allow the working tool or component to tilt in order to follow the camber of the road surface, if necessary.

[0010] In a preferred case, the road working tool comprises a roller for compacting road workings, either on the road surface or in a trench in the road, the roller being arranged so as to rotate about a horizontal axis. Preferably the roller is of large dimension so as to provide considerable mass and so as to ride easily, by virtue of its large curvature, over the road workings which it has to compact.

[0011] The roller may be carried by a frame and the frame and roller are capable of swinging about the said castoring axis.

[0012] The roller may be of the order of 1500 mm in diameter and it may be constructed so that it can comprise one, two or three ring sections, for example each of 700 mm width rolled steel bar. The ring sections may be adapted to be bolted together and the frame may be large enough to carry the roller when it is made up of one, two or three sections. The roller will normally run in road trenches, compacting fill material and therefore the number of sections used will depend upon the trench width.

[0013] The roller may be adapted to be vibrated, by suitable vibration means, when it is performing a compaction operation.

[0014] In an alternate embodiment, the tool is a compaction plate for working on the road surface or a compaction plate for working in a trench in the road; the plate may also be adapted to be vibrated.

[0015] The invention also provides an attachment for use with a vehicle to provide road working equipment as aforesaid.

[0016] Embodiments of the invention in its various aspects will now be described, by way of example, with reference to the accompanying diagrammatic drawings, wherein:-

Fig. 1 is a side elevation of a skid steer vehicle with attachment according to the invention;

Fig. 2 is an illustrative plan view to explain the steering arrangements of the vehicle and attachments shown in Fig. 1;

Fig. 3 is a view similar to Fig. 1, but showing a modified constructional arrangement to permit the positioning of the working tool further from the mounting vehicle;

Fig. 4 is a plan view of the arrangement shown in Fig. 3;

Fig. 5 is a side view similar to Fig. 1, but showing, according to a second aspect of the invention, the utilisation of a road surface compacting plate;

Fig. 6 is a plan view of the arrangement shown in Fig. 5;

Fig. 7 is a view similar to Fig. 5, but showing the utilisation of a compaction plate for working in the base of a road trench;

Fig. 8 is a plan view of the arrangement shown in Fig. 7;

Fig. 9 is a perspective view of a vehicle with an attachment according to another embodiment of the invention;

Fig. 10 is a side view of the wheel assembly of the attachment shown in Fig. 9; and

Fig. 11 is a sectional view taken on the line A-A in Fig. 10.

[0017] Referring to the drawings, a skid steer vehicle 10 is of conventional type, and is provided with four ground engaging wheels or rollers 12, 14, 16, and 18, the rollers 12 and 14 being on a common axis and being in this example the rear wheels, whilst the wheels 16 and 18 are also on a common axis and are the front wheels. The vehicle 10 which is of conventional construction may be provided with an engine compartment 20 and a driver cabin 22. Other forms of skid steer vehicles are constructed differently.

[0018] The vehicle is steered by controlling the drive to the respective rear wheels 12 and 14 insofar as these wheels can turn differentially in order to effect steering of the vehicle. For sharp steering manoeuvres, the wheels 12 and 14 can be driven in opposite directions to give turning of the entire vehicle when all four wheels are on the ground about the axis 23.

[0019] The vehicle is provided with a pair of loader arms 26 which can be raised and lowered by means of hydraulic ram devices 28, and at their extremities the arms 26 support a roadworking attachment 30. The arms 26 are connected to a bracket 32 of the attachment which is in turn connected to a face plate 34. Mounted on the face plate 34 is a working tool head 36 which can castor about an axis defined by shaft 38 by which the head is connected to the plate 34. The bracket 32 is connected to the arms 26 at horizontal axis 40, which is located rearwardly of the castoring axis 42 of the head 36. The face plate and working head 30 can be tilted about axis 40 by means of a hydraulic ram 41 connected between the arms 26 and the plate 34 as shown in Fig. 1.

[0020] Head 36, in the example shown, is provided with a road rolling drum 44 and it has suitable vibratory drive means 46 for such drum in order to vibrate same to compact as well as roll the road surface or sub-surface. It is to be mentioned that the type of roadworking tool can be varied and instead of a roller 44 there may be a slitting cutter disc, or a planer drum for planing the road surface or a plate compacting tool.

[0021] By lowering the arms 26 using the rams 28, the front end of the vehicle can be caused to be raised from the ground as illustrated in Fig. 1 so that the wheels 16 and 18 are clear of the road surface. In this position, when the vehicle is steered by differential driving of the wheels 12 and 14, the steering axis of the vehicle in effect moves rearwards, and in fact when the wheels 12 and 14 are driven in opposite directions, the steering axis of the vehicle lies on point 24 as shown in Fig. 2 mid-way between the wheels 12 and 14 and on the common axis of said wheels. The raising of the front end of the vehicle as shown in Fig. 1 causes the weight of the vehicle to be transferred through the arms 26 onto the roller 44. This provides an advantage that when the vehicle is operating on an undulating surface, then there is no tendency for the roller 44 to be raised clear of that surface as might be the case if all four wheels were maintained on the ground.

[0022] By the combination of castoring the tool head 36 and raising the front of the vehicle, when the vehicle 10 is steered as above described, the head 36 will castor relative to the face plate 34 and arms 26 to ensure smooth working of the tool despite substantial steering movements of the vehicle.

[0023] By steering using the rear of the vehicle only, and it should be mentioned that the vehicle can be a tractor vehicle as opposed to a wheeled vehicle, dramatic improvement in the steering control is achieved as compared to steering when all four wheels are on the ground. If working takes place using four wheel steering and the tool is a compactor plate working in a trench, the compactor plate is rapidly at one side of the trench or the other and only a short compaction plate can be used, but by incorporating the castoring of the working tool in conjunction with the raising of the front of the vehicle, a far more controllable machine is produced in which the downward pressure on the compaction equipment is maintained.

[0024] The head 36 may be mounted on the plate through suitable rubber mountings in order to isolate the vehicle from the vibrations created in the working head, and the said mountings may also be such as to enable the working head adjust angularly about a horizontal axis to take account of the of the road surface on which the apparatus is working.

[0025] The vehicle instead of having rollers or wheels 12-18 may in fact have tracks.

[0026] Referring now to Figs. 3 and 4, the arrangement illustrated is similar to that shown in Figs. 1 and 2, and therefore the same reference numerals have been used where appropriate, and in fact the only difference is that between the face plate 34 and the head 36 there is a supporting bracket 50 which positions the head 36 much further in advance of the vehicle 10. The principle of operation of the machine shown in Figs. 3 and 4 is identical to that described in relation to Figs. 1 and 2, except that when the vehicle is being steered in the Fig. 3 position so that it is rotating about axis 24, then the roller 44 will travel more linearly in a direction transverse to the axis of the vehicle. In other words the travel of the roller will be more similar to transverse rolling. The machine shown in Figs. 3 and 4 is particularly useful for the rolling of a rectangular patch of tarmacadam or road surfacing material in a road. To roll the patch, the vehicle can be caused to propel back and forth in a first stage of compaction, and in a second stage can be operated in a steering fashion enabling the roller 44 to roll transversely back and forth over the rectangular patch.

[0027] The arms 26 may conventionally support an excavator shovel or bucket and the attachment 30 is preferably adapted to be connected to the arms 26 in place of such shovel or bucket.

[0028] The working tool 44 may work on the surface of the road or in a trench provided therein as appropriate, and the respective tools for connection to the head 36 may be each capable of being connected thereto in substitution for another. The head may furthermore have several tools and be adapted for performing different types of operations.

[0029] Turning now to Figs. 5 to 8, in a second aspect of the invention, the working tool is a plate compactor, and Figs. 5 and 6 show equipment similar to Figs. 3 and 4 (and hence similar reference numerals are used) but in the arrangement of Fig. 5, the head 36 is in the form of a plate compactor for resting on the road surface. The compactor will be provided with a vibrator, and it is also pivotable about a castoring axis 42 similar to the head 36 shown in Fig. 3. Again in Fig. 5 and in Fig. 6 the extension arm or bracket 50 is used, but it should be pointed out that this is not essential. Steering movements are effected in a similar manner.

[0030] In the arrangement shown in Figs. 7 and 8, again a compactor plate is utilised, but this compactor plate which is illustrated by reference 52 is at the lower end of an extension leg 54 connected to the head 36 to enable the compactor plate 52 to be located in and work on the base of a roadway trench 56. Fig. 8 illustrates how the plate 52 can effect steering movements to follow the line of the trench, by virtue of being pivotable about the castoring axis 42.

[0031] The equipment illustrated in Figs. 5 to 8 operates essentially in the same manner as described in relation to the equipment of Figs. 1 to 4, the only difference being that compaction plates are used. The combination of a compaction plate and a vibrator used in conjunction with vehicles such as skid steer vehicles or small tracked excavators, constitutes an aspect of the present invention. The particular utilisation of a compacting plate for operation in a trench is a particular novelty. The provision of the compacting plate in conjunction with the steerable axis 42 enables the compacting plate to follow the line of a trench which is other than perfectly straight.

[0032] The vibration mechanism embodied in the head 36 may be of conventional construction and of a type used in vibrating road roller vehicles.

[0033] Additionally, the roadworking tool 44 may in fact be a sweeping brush if required.

[0034] When the working tool is compaction equipment such as a roller or plate or both, it is preferable that such equipment should be adapted to work in narrow trenches and on the road surface.

[0035] The rear wheels 12 and 14 or the rear ends of the tracks when provided are used as the propulsion system for the vehicle and attachment to enable the equipment to advance slowly, and in addition to being used as the steering means for the system.

[0036] For particular operational steps it may be desirable to provide the apparatus with releasable locking means to prevent the head from moving in a steering fashion. It is also within the scope of the invention to provide shearing means such as a hydraulic ram or other mechanical means for the head.

[0037] The vibrator which is used in the equipment, when provided preferably is a hydraulically driven vibrator.

[0038] In the embodiment of the invention illustrated in Figs. 9-11, the construction is more or less the same as that illustrated in Figs. 1 and 2, except that the roller 100 is of substantial diameter e.g. of the order of 1600-2000 mm so that its surface has a greater curvature, and it is of greater mass. These features combine to enhance compaction. As shown in Fig. 10, the roller 100 essentially is for rolling in a trench 56 to compact the fill material therein, and the roller is held in an A frame 102 by means of a shackle 104. The shackle 104 is mounted for pivoting about the castoring axis 42 corresponding to the axis 42 shown in Fig. 1 on the frame 102. The A frame is secured to the skid steer loader arms 26.

[0039] The roller 100 is shown as being made up in three sections 100A, 100B and 100C. These sections are bottled together by bolts 108 as shown and sections 100B and 100C may be individually removed so that the roller can be of different widths depending upon the width of the trench in which the roller is to operate. The roller sections are bolted together, but are designed to be removable selectively by unbolting same, as will be understood.

[0040] As shown in Fig. 11, the sections 100A, 100B and 100C are channelled sections, and the centre section 100B is secured to a wheel disc 106 which is apertured as shown in Fig. 9. The disc 106 may be welded to the channel 100B, or may be bolted thereto by means of the same bolts 108 which secure the sections together. It is also to be noted from Fig. 10 that the sections 100A, 100B and 100C are in quadrants to facilitate manufacture and assembly.

[0041] Fig. 11 shows that instead of providing the outer sections 100A and 100C, smaller width angle sections 100X may be provided, as shown in dotted lines, which have bosses 110 which are threaded and which may be secured to the outer flanges of the central section 100B. The angled sections 100X are half the width of the channel sections 100A and 100C, which provides that the width of the wheel 100 may be varied considerably.

[0042] The apparatus shown in Fig. 9 may also be provided with a vibration means in order to vibrate the roller when it is working to enhance compaction. The arrangement of Fig. 9 operates essentially in all respects similar to the embodiments hereinbefore described, and any preferred feature of any of the embodiments hereinbefore described can be used in conjunction with the apparatus shown in Fig. 9, and such apparatus possesses all of the advantageous features of the invention as referred to herein.

Claims

1. Road working equipment comprising a vehicle having a road working attachment coupled to the vehicle by a means enabling the attachment to turn about a castoring axis so that when in use the vehicle is steered from a straight line movement, the working tool can change its angular relationship relative to the ground by virtue of castoring about said axis.

2. Equipment according to Claim 1, wherein the vehicle is a low speed transmission vehicle such as an asphalt paver or a skid steer vehicle.

3. Road working equipment according to Claim 1 or 2, wherein the attachment is carried on arm means extending from the vehicle, said arm means being capable of being jacked to thrust the road working tool into firm engagement with the road surface.

4. Road working equipment according to any preceding claim including a vibration means for vibrating the tool when it is working on the road surface or road material.

5. Road working equipment according to any preceding claim, wherein the road working tool is a roller mounted for rotation about a horizontal axis.

6. Road working equipment according to Claim 5, wherein the roller has a diameter in the order of 1500 mm.

7. Road working equipment according to Claim 6, wherein the roller is made up of a plurality of roller sections which are detachable from and connectable to each other whereby the width of the roller may be varied.

8. Road working equipment according to any of Claims 1 - 4, wherein the tool is a compaction plate.

9. Road working equipment substantially as hereinbefore described with reference to any of the embodiments in the accompanaying drawings.

10. An attachment for use in connection with a vehicle to form road working equipment according to any one of the preceding claims.

Drawing