GROUND CONTOURING APPARATUS WITH PROVISION FOR MOUNTED ACCESSORIES

Abstract

Disclosed is a ground modifying apparatus of a type sometimes known as levellers, typically as used on tractors and skid-steer vehicles. In current practice these are used for preparing, levelling, and contouring the ground. Such device includes at least an accessory body portion supporting a ground modifying accessory or includes a way to attach the same. The apparatus includes a travelling carriage assembly pivotably attached by a carriage pivot, about a rotational axis substantially parallel to a longitudinal axis of the apparatus. The carriage pivot is positioned lower than the center of gravity of the travelling carriage assembly.

Claims

1. A ground modifying assembly comprising at least an accessory body portion supporting a ground modifying accessory or includes means for the attachment thereof, said ground modifying assembly including a travelling carriage assembly which is pivotably attached by a carriage pivot, about a rotational axis substantially parallel to a longitudinal axis of said ground modifying assembly, to said ground modifying assembly; said carriage pivot characterised by being positioned lower than the centre of gravity of said travelling carriage assembly.

2. A ground modifying assembly, as claimed in claim 1, which includes a body mounting portion for connection to a vehicle or a support depending from a vehicle, said arrangement further characterised by having multiple linkages extending and connecting said accessory body portion and body mounting portion, and where a link may comprise one or more of either or both of: a fixed length linkage, and an actuator.

3. A ground modifying assembly, as claimed in claim 2, in which there are present at least two sets of linkages between the accessory body portion and body mounting portion, each set of linkages comprising at least two links, and wherein there is present a set of linkages outwardly displaced from and either side of the longitudinal centre axis of said ground modifying assembly.

4. A ground modifying assembly, as claimed in claim 3, in which the arrangement allows for relative vertical movement of said body mounting portion relative to body mounting portion, but resists relative alteration in the pitch of one to the other.

5. A ground modifying assembly as claimed in claim 4 in which links in a set of linkages are substantially parallel one to the other.

6. A ground modifying assembly as claimed in claim 3 in which said sets of linkages allow roll rotation of said accessory body portion relative to said body mounting portion, about an axis substantially parallel to the longitudinal axis of said ground modifying assembly.

7. A ground modifying assembly as claimed in claim 6 which includes at least one actuator to effect said roll rotations of said accessory body portion relative to said body mounting portion.

8. A ground modifying assembly as claimed in claim 2 in which a ground modifying accessory comprises at least one of: a blade, a mouldboard, a powered drum, a powered drum with protruding features, and a rake.

9. A ground modifying assembly as claimed in claim 2 in which a ground modifying accessory comprises a blade or mouldboard, and there is second a second ground modifying accessory ahead of said blade or mouldboard.

10. A ground modifying assembly as claimed in claim 9 in which second ground modifying accessory is mounted on a pivoting transverse mount, at least one actuator allowing for pivoting of said transverse mount between accessory raised and accessory lowered positions.

11. A ground modifying assembly as claimed in claim 2 which includes a scarifier module comprising a plurality of tines, pivotably attached to the accessory body portion about a substantially transverse axis.

12. A ground modifying assembly as claimed in claim 1 in which said travelling carriage assembly can be pivoted upwardly about a substantially transverse axis to rest substantially above said accessory body portion.

13. A ground modifying assembly as claimed in claim 2 in which said body mounting portion comprises a connection for one of: an excavator arm bucket linkage, a standard quick-hitch arrangement for skid-steer loaders, a linkage for tractor arms.

14. A ground modifying assembly as claimed in claim 2 which includes at least one positional aid comprising at least on of the set comprising: a sensor, transmitter, and transceiver; a said positional aid being associated with a guidance system, and wherein information is passed from said positional aid to a control system controlling one or more actuators affecting the relative position between said accessory body portion and body mounting portion.

15. A ground modifying assembly as claimed in claim 1 when attached to a vehicle.

Description

DESCRIPTION OF DRAWINGS

[0168] FIG. 1 is a partial plan view of one preferred embodiment of the present invention,

[0169] FIG. 2 is a perspective view of the embodiment of FIG. 1 in an alternative configuration,

[0170] FIGS. 3a-3c are front views of the embodiment of FIG. 1, where FIG. 3a illustrates the blade in a lowered position (about a forward axis), FIG. 3b illustrates the blade in a raised position (about a forward axis), and FIG. 3c illustrates the blade in an inclined position (about a forward axis),

[0171] FIG. 4 is a perspective view of an alternative embodiment of the present invention in a folded configuration,

[0172] FIG. 5 is a side diagrammatic view of the embodiment of FIG. 3,

[0173] FIG. 6 is a side diagrammatic view of FIG. 4 in an extended configuration,

[0174] FIG. 7 is a perspective view of the embodiment in FIG. 6,

[0175] FIG. 8 is a side diagrammatic view of a further embodiment of the present invention attached to the existing blade of a vehicle, and

[0176] FIG. 9 is a perspective view of the embodiment of FIG. 8,

[0177] FIG. 10 is a partial perspective view of an embodiment of a ground contouring assembly showing an embodiment of a rotatable accessory mounting portion, without fitted accessory, in an accessory retracted position,

[0178] FIG. 11 is a part side view of the embodiment of FIG. 10 with an embodiment of an accessory comprising a power drum fitted and in a position between retracted and engaged configurations,

[0179] FIG. 12 is a side perspective view of an embodiment of a ground contouring assembly with the embodiment of a power drum of FIG. 11 in an accessory engaged position,

[0180] FIG. 13 is a cross-sectional transverse plane diagrammatic view of a power drum as used in the embodiments of FIGS. 11 and 12,

[0181] FIG. 14 is a side perspective view of an embodiment of a ground contouring assembly illustrating laser guidance receivers and mounts,

[0182] FIG. 15 is a perspective view of an embodiment of a scarifier accessory module,

[0183] FIG. 16 is a top-side perspective view of an alternative embodiment of a ground contouring assembly showing a fixed transverse mount arrangement with an embodiment of a scarifier module, and an alternative embodiment of a forward support carriage arrangement,

[0184] FIG. 17 is a top side perspective view of a further embodiment of a ground contouring assembly ground contouring assembly capable of yaw and pitch adjustment of the accessory body portion.

[0185] FIG. 18 is a side diagrammatic view of the embodiment of FIG. 17 in which the accessory body portion is pitched forwardly,

[0186] FIG. 19 is a plan diagrammatic view of the embodiment of FIGS. 17 and 18 with wheels in folded position and in which the yaw of the accessory body portion about a vertical z-axis has been adjusted,

[0187] FIG. 20 is a front diagrammatic view showing the general principles of a preferred embodiment of a low pivot carriage/walking beam,

[0188] FIG. 21 is the schematic diagram of the embodiment of FIG. 19 with the carriage portion pivoted out of the ground plane,

[0189] FIG. 22 is a partial side view of the embodiment of a preferred embodiment of the present invention,

[0190] FIG. 23 is a partial left side, bottom-rear perspective view of the embodiment of FIG. 2,

[0191] FIG. 24 is a partial plan view of the embodiment of FIG. 2, and

[0192] FIG. 25 is a partial left side, top-front perspective view of the embodiment of FIG. 2.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0193] With reference to the drawings (particularly FIGS. 1 and 2), and by way of example only, there is provided a ground contouring assembly (generally indicated by arrow 1) comprising a body attachment portion (generally indicated by arrow 2) and an accessory body portion (generally indicated by arrow 3);

the two body portions (2, 3) being connected by body connecting linkages (5-7) which allow a substantially translational movement of the accessory body portion (3), substantially parallel and relative to the accessory body portion (2)see for instance FIGS. 3a and 3b;
the body connecting linkages (5-7) also allowing a rotational movement of the accessory body portion (3), relative to the body attachment portion (2), about a rotational axis substantially in the direction of forward travel (9) of the assembly (1)see for instance FIG. 3c;
said body connecting linkages including linear actuators (5a, b), there being at least one linear actuator (5) being present either side of the middle (10) of the ground contouring assembly (1) when viewed in plan;
said body connecting linkages (5-7) also including at least one pivot-ended stabilising linkage (6-7) either side of the middle (10) of the ground contouring assembly (1) when viewed in plan;
and wherein the body connecting linkages (5-7) assist in maintaining relative movement of the body portions to as described above.

[0194] The body attachment portion (2) includes a quick-hitch arrangement (4) such as commonly used on skid-steer tractors.

[0195] With reference to FIG. 3 in the illustrated embodiment (1) there are two hydraulically controlled upper linear actuators (5a, b) which can be independently controlled to alter the relationship of each end of the blade portion (3) relative to the body attachment portion (2). This is best illustrated in FIG. 2, where right hand actuator (5b) is contracted relative to left hand actuator (5a) to adopt a configuration such as shown in FIG. 3c. While lower linkages (7) may comprise connecting arms, these may also comprise hydraulically controlled lower linear actuators which work in cooperation with actuators (5) to allow the accessory body portion to adopt the configurations shown in FIG. 3, and combinations thereof. This arrangement can also allow for alteration of the inclination of the blade (11) about a transverse axis, under the control of the operator.

[0196] The stabilising linkages, pivot-ended linkages (6a, b) (7a, b) have ball joint ends where they attach to at least one of the body portions (2, 3) which is necessary to allow for the permitted relative movements of the body portions (2, 3). In the present invention a spherical bush is used in the jointsthis joint (14) can be clearly seen in the stabilising arms (6) where they (in this embodiment) attach to a central mounting point (15) on the body mounting portion (2).

[0197] The geometry of the remaining connecting linkages (stabilising arms (6-7)) assist in maintaining the relationship between the two body portions (2, 3) as movement occurs (such as shown in FIG. 3). In this arrangement the distance of separation between the body portions (2, 3) remains substantially the same, as does their relative forward/rearward inclinations (i.e. inclination being rotation about a transverse axis) relative to each other (though some flexibility is allowed here in the design of the geometry in various embodiments).

[0198] The primary permitted relative movements between the body portions (2, 3) are, when viewed from the front and wherein the body attachment portion (2) is considered fixed in position, relative upward and downward movement of the accessory body portion (3) relative to the body attachment portion (2), as well as allowing relative upward and downward movement of each end of the accessory body portion (3) relative to the body attachment portion (2)allowing also for inclination of the blade portion (3) (relative to the body attachment portion (2)), such as shown in FIG. 2.

[0199] Accordingly there is provided a precise alteration of the elevation and rotational inclination of the blade relative to the quick hitch (4) (which follows the roll inclination of the vehicle in response to ground contours) without the need for heavy and expensive quick hitch rotational attachments. The arrangement of the illustrated embodiment theoretically provides for faster (quick response movements are important for a moving vehicle) changes to the elevation and rotational inclination of the blade, as well as being much more precise.

[0200] The actuators can also be coupled to a laser levelling control system (sensors or emitters can be mounted on arms (not shown) which fix at positions (12) on the blade portion (3)) so that the blade (11) is maintained at true ground elevation and the horizontal, regardless of any pitching and rolling movements of the vehicle to which it (1) is attached. As mentioned above, the quicker responsiveness of the present embodiment also allows the vehicle to travel faster.

[0201] Preliminary trials by the inventor, have indicated that the present invention when used with a laser levelling system can level ground to a much higher degree of precision (3 mm compared to 10 mm) approximately 12 times faster than when using a similar arrangement with a prior art device. This represents a very significant advance in the art in terms of productivity and precision. Accordingly this also opens the present invention up to other applications where a tool on a moving vehicle needs to be maintained at a precise inclination and elevation.

[0202] In FIGS. 4 and 5 we see a folding embodiment of the present invention, where a provided stabilising arm assembly (30) has a folding end portion (31) on which a ground contacting stabilising wheel arrangement (32) is mounted.

[0203] In FIG. 5 the reduced front to rear length of the apparatus is evident, as are the potential transport benefits. Similarly, the closer proximity of the blade (11) to the front of the apparatus, for close work, can be gauged.

[0204] In FIGS. 6 and 7 we see a further embodiment suitable for attachment to an excavator. Rather than a quick hitch (4) we have an arm arrangement (50) to which is pivotably attached (53) a T-pin (51) comprising a quick hitch adaptor (which may be of different quick connect configurations) to which the quick hitch adaptor (54) of an excavator's (not shown) dipper arm (52) may be attached. This arrangement makes the ground contouring assembly available for use with excavators, a new and novel arrangement which significantly improves the versatility of both excavators and levelling devices.

[0205] In FIGS. 8 and 9 we see an alternative mounting system to the ubiquitous quick hitch (4), the body mounting portion (70) attaching to the existing blade (71) of a vehicle (not shown for simplicity).

[0206] Here at least one upper hook portion (72) affixed to the body mounting portion (70) hooks over the top of the existing blade (71). A contacting bar (78) may be provided on the body mounting portion (70) to help accommodate the different curves of blades and reduce possible damage to the blade (71).

[0207] A lower hook portion (73) connected by a flexible linkage (74) to an adjustable linking element (75), in turn connected to an element (79) associated with the body mounting portion (70), helps secure the ground contouring assembly (1) to the existing blade (71) as the adjustable element(s) (75) are tightened. The adjustable element (75) may simply be a turnbuckle in a preferred element, and may be provided with an arm (76) to help tighten the turnbuckle, and provide additional stabilisation when the distal end of the arm (76) is connected to a point (77) on the accessory body portion (3) after tightening.

[0208] In FIG. 10 we see an embodiment of a modified ground modifying assembly including a rotatable accessory mounting portion (101) comprising a transverse accessory mount (102), in simplest form comprising rectangular hollow section bar, connected at each end to side supporting elements (in this case comprising side guards) (106) by rotatable mounts (105) allowing at least partial rotation of the mount (102) about a transverse axis substantially in parallel with the general plane of the blade (11) or mouldboard (107) of the accessory body portion.

[0209] Linkage tabs (104a,b) allow for control of the rotation of the mount (102) by allowing the connection of mount rotation means comprising linear actuators (103a,b). In preferred embodiments these are hydraulic and capable of progressive and continuous control by the operator, and/or could be linked into an automated control system. In this figure the mount (102) is shown in an accessory retracted position.

[0210] In FIGS. 11 and 12 we see the inclusion of a power drum assembly (generally indicated by arrow 110) such as a Harley rake (114) to the rear of structure support wheel (32). Features such as teeth or studs (115) may be provided on the Harley rake drum (114). While the invention allows for such an assembly (110) to be attached directly to side supports (106) by a rotatable mount (e.g. 105) at each end, the preferred arrangements utilise the rotatable transverse accessory mount (101) of the embodiment of FIG. 10 for easier fitment and removal of accessories (e.g. 110).

[0211] FIG. 12 provides a perspective view of the embodiment of FIG. 10 with the power drum accessory (110) of FIG. 11 (and such as detailed in FIG. 13) fitted and in the engaged position.

[0212] FIG. 13 illustrates a preferred power drum accessory (110) arrangement such as would be used in preferred embodiments as described in relation to FIGS. 11 and 13. As mentioned in the main body of the specification it is desirable for operators to be able to work close to boundaries and obstructionse.g. foundation walls, kerbing, marker poles, etc. In practice this can usually be achieved in embodiments of the invention by minimising protrusions outside of the width of the blade (11), or as more readily seen in the pictures, outside of the side guards 106.

[0213] While the power drum could utilise a compact external hydraulic motor at each end the option for preferred embodiments is predominantly inboard hydraulic motors (112a,b) positioned largely within the drum (114) itself. In this situation only the protective cap and mount (111a,b) need extend outside of the planes defined by the side guards (106) while allowing the drum (114) to extend the full width within the extended vertical planes defined by the side guards (106).

[0214] The protrusions (115) from the drum (114) are defined by choice, and may be replaceable elements or formed into drum (114) itself. The user is open to choice here. Various types of teeth, blades, features may be provided along with different combinations thereoffor instance the user choice for breaking asphalt and road-seal may be different from dethatching and preparing areas covered with vegetation.

[0215] Less destructive drum choices are also envisagedfor instance the power drum may comprise a brush for finishing and screening areas, finishing landscaped areas or lightly covering sown seed, or even removing excess materials and debris on finished areas (e.g. gravel chips on finish tar sealed roading and sidewalks etc). It is intended that there will be user choice in the selection of the properties of the power drum in a power drum assembly (110).

[0216] FIG. 14 illustrates a different perspective view of the embodiment of FIG. 12, and also shows the laser receiver unit (116a,b) guide poles (117a,b) which can employed with various embodiments of a ground contouring assembly (1) to enable it to be used a laser guidance and levelling system, or full 3D guidance system, such as becoming more common in the industry. There are various manufacturers of such systems (including, for instance, Leica) which can provide accessory guidance and control systems able to work with position transmitters and solutions for use on various sites (and types of site). A potentially realisable advantage of various embodiments of the present invention is that when such laser assisted systems are used, any mounted accessories on the accessory body portion also operate under the same laser assisted control as the blade and benefit from the advantages thereof. Hence a ground contouring assembly of the present invention to which various accessories can be fitted provides a useful advance in the industrythe multiple linkage arrangement connecting the accessory body portion to the body attachment portion allows for angling of the accessory under operator control and/or in response to laser assisted control systems. No prior art accessories such Harley rakes/power drums, scarifiers, etc are able to be angled in response to changing ground contours and this represents a significant disadvantage (multiple passes with different accessories) in terms of time and accuracy for land and site preparation and contouring.

[0217] The following specifications in relation to the embodiments of FIG. 10 through 15 are not intended to be limiting but representative only of a currently most preferred embodiment, and to provide additional information to the skilled reader in understanding a best preferred embodiment of the invention. However, it should be appreciated that many of these parameters are open to user choice and to suit a particular job. [0218] Typical Drum diameter: 170 mm (without teeth) [0219] Typical Drum working width: 1.940 mm [0220] Drum type: Steel, reversible in operation without affecting levelling operation [0221] Typical Motor displacement (per side): 160-380 cc, depending on base machine size and hydraulic flow [0222] Typical Drum speed: adjustable from 0 to 240 RPM [0223] Typical Shaft diameter: 50 mm [0224] Typical Number of teeth: 96 [0225] Typical Tooth type: 16 mm tungsten with button or flat top, depending on type of work [0226] Typical Tooth height (from surface of drum): 30 mm [0227] Typical Type of drive: Direct with resilient internal toothed drive [0228] Typical Lubrication and maintenance points: zero, grease free pivots, internal, oil lubricated bearings [0229] Typical Drum support bearings: 2 internal, oil lubricated, maintenance free [0230] Typical Angle of retraction: 90 degrees to operating plane [0231] Typical Engagement depth: Infinitely adjustable in operation from 100 above to 70 mm below blade height [0232] Typical Stone barrier set height: 3 position in 40 mm increments [0233] Typical Clearance height with drum removed: 560 mm [0234] Typical Drum forward length from blade: 540 mm [0235] Typical Drive motor extension width past side wing gusset: 20 mm [0236] Typical Weight of drum and mount structure: 200 KG [0237] Typical Weight of pivot mounting structure: 40 KG [0238] Typical Locking mechanism: Over centre latch mechanism with positive tension in lock position [0239] Typical Tilt from level: adjustable in manual or automatic mode, 0 to +/12 degrees [0240] Typical Control method: proportional hydraulic positioning using electronic machine control [0241] Typical Grade Control: continuous automatic from 2D laser or 3D data file, Dual GNSS or TPS capable [0242] Typical Tooth engagement depth: manual set via hydraulic cylinders [0243] Typical Maximum main fall: set by laser, typical 0-15% [0244] Typical Maximum cross fall: set by laser, typical 0-15% [0245] Typical Accuracy of cut: Typical +/3 mm from registered grade [0246] Typical laser system provider which might be employed on embodimentsLeica

[0247] FIG. 15 illustrates another accessory which may be fitted by an operator to an accessory mount (102). In this case a scarifier module (121) comprises a plurality of tines (123) are connected to an accessory mount portion (122) for fitting to the transverse mount (102). A pivot pin(s) (not shown) aligned with axis 124 allows for forward pivoting of the tines (123) allowing for them to drag freely when the ground contouring assembly is being reversed in operation. Alignment pins (125a, b) maintain spacing of the tines.

[0248] Apertures (126) and (127) in the mount and tine portions respectively allow an operator to temporarily lift the tines (123) and place a pin in to lock them in an up position. This can be useful for improving visibility for the operator in certain operations where the tines are not required. This can still used in conjunction with rotation of the transverse mount (102) to further lift the tines (123).

[0249] Not visible is a rear tab or bar at the rear of the mount ribs (128) which limits rearward travel of the tines (123) during forward movement of the ground contouring assembly (1), and to allow the tines (123) of the module (121) to be raised when the accessory bar is moved to an accessory retracted position.

[0250] It should also be envisaged that the scarifier modules could be positioned directly in front of the blade and mouldboards of the ground contouring assembly to allow them to be used in conjunction with another accessory on a transverse accessory mount (102), allowing an operator to readily use both in conjunction or alternate between use of the two accessories with relative ease of operation and adjustment. It should also be appreciated that a single scarifier module extending the full width of the mount (102) could be used, or multiple smaller modules used as required.

[0251] FIG. 16 illustrates a further modification to various embodiments of the present invention. In practice it is sometimes necessary for operators to work around obstructions on a sitethese may be foundations for pillars or columns, and such like. As an alternative to the larger folding wheel carriage assembly (31, 32) of some embodiments of the invention, a simplified pivoting carriage with single pivot (132) can be provided and attached to a forwardly extending support (133), which may be fixed or removable. This arrangement gives a greater unobstructed distance (134) between the wheels (134) and projected general vertical plane of the side guards. This increased clearance make it easier for an operator to work close to, and around, obstructionspotentially providing a cleaner job with minimal manual follow up to finish problem areas. It should be noted that in a number of situations a forward carriage is desirable to help stop the ground contouring assembly (1) from nosing down into softer materials and maintaining a more accurate natural level for the tractor and ground contouring assembly combination.

[0252] As a variation of the aforesaid embodiments, there are occasionally situations where an operator may require additional flexibility in terms of being able to manipulate the orientation of the accessory body portion (203). Such operations may include tilting the accessory body portion forwardly or rearwardly (about a transverse axisi.e. altering the pitch of the accessory body portion). Other operations may include rotating the angle of the accessory body portion (203) about a vertical z axisi.e. a yaw type movement. And various combinations of these operations and that of previously described embodiments. It should also be appreciated that these operations also affect any accessories which may also be mounted on the accessory body portion (203).

[0253] In order to achieve these additional operations, various linkages of the previous embodiments (e.g., FIG. 8) may be substituted with linear actuators.

[0254] FIG. 17 refers a modification of embodiments such as shown in FIG. 8. For instance, to achieve pitch adjustment, linkages (7) (e.g. FIG. 8) of the previous embodiments are substituted with linear (typically hydraulic) actuators (207). These can be lengthened or shortened (ideally in tandem) to adjust pitchwe shall assume that other linkages/actuators remain at constant length while visualising this. Once a desired pitch has been achieved, their length may be maintained to retain this relative pitch (though see also more sophisticated embodiments discussed later). The beauty of this arrangement is that the actuators (207) function primarily as adjustable linkages, enabling these variant embodiments (e.g. FIG. 17) to still operate in the manner of the embodiment of FIG. 1 (for instance).

[0255] Providing linear actuators (206) to replace linkages (6) of FIG. 1 allows for the aforesaid yaw-like adjustments to be made. Here the operation is a little different and will typically involve extending one actuator (206) while retracting the other (206). The geometry is also a little different and these actions may also cause some roll-movement of the accessory body portion (203). While this might be acceptable in some embodiments, providing actuators (207) instead of fixed length linkages (e.g. 7) can help compensate and allow adjustment to reduce these other pitch and/or roll changes when adjusting yaw.

[0256] In practice it is likely that an operator may employ changes to any one or more of pitch, yaw, and roll simultaneously. It is envisaged that in most cases the operation of such advanced embodiments of the present invention will be in conjunction with laser assisted control systemssuch as, for instance, provided by companies such as Leica. In these cases a control system for the actuators (205, 206, 207 where provided) will be coupled with the laser assisted control system to ensure the accessory body portion (203) is maintained at the correct attitude/position as the leveller and vehicle travels across terrain.

[0257] It is envisaged that even with laser assisted embodiments, the operator may have direct (or indirect fly-by-wire type) control over pitch and yaw, as these are often more influenced by the type of terrain and material that the ground contouring assembly is working on. It also envisaged that these embodiments may also be used on non-laser assisted embodiments of a ground modifying assembly with direct control of the actuators (205-207 where provided) by the operator. There may also be fly-by-wire type assisted operation using computational means with a control system to enable the operator to more easily attain a particular attitude of the accessory body portion (203)it is envisaged that such embodiments might even used modified joysticks or roller-ball type controls for the operator, rather than individual controls for each actuator and/or set thereof (i.e. 205-207 where provided). FIG. 18 illustrates the embodiment of FIG. 17 in which actuators (207) have been shortened to enable the accessory body portion to pitch forward relative to the ground (220)3. Once these actuators (207) have been set and maintained at the required length, and assuming also that actuators (206) are also maintained at constant length (assuming these are present instead of linkages (6)) then operation of actuators (205) will raise and lower the accessory body portion (203) while maintaining substantially the same pitch. In fact, operation of actuators will be substantially the same in effect as for the embodiment of FIG. 1.

[0258] With reference to FIGS. 20 and 21, and prior art ground modifying assemblies with walking beams, existing prior art walking beams (carriages supporting forward wheels) have their walking beam pivot point above the walking beam, which is significantly above the contact point of the tyres. This pivot is to allow the carriage to rotate about a longitudinal axis (with respect to the leveller/ground modifying assembly) to allow wheels on the carriage to negotiate bumps and contours in uneven ground being worked.

[0259] As all other manufacturers position their pivot point in this position, the applicant had also assumed this to be the correct point, as the walking beam always hangs level when raised off the ground. However, this has turned out not to be the case.

[0260] When a ground modifying assembly is turned (particularly in reverse) with the wheels raised at all, the natural motion of the pendulum action of the suspended weight of the walking beam and wheels assembly causes the leading wheel in the turn to contact the ground. This is due to the centre of gravity being below the pivot point. If the material is soft (which is the case at the end of a push (forward operation of a ground modifying assembly) as it has not had a blade or ground modifying accessory pass over it to compact/level/contour it, the contacting wheel makes an impression in the ground. In addition, the wheel may be pivoting around to change direction, further compounding the impression in the soft material. This immediately causes the walking beam to increase in angle, further amplifying the problem. The walking beam will then act as an anchor and drive the wheel into the soft ground, as the high pivot point creates a high angle of attack to try and force the whole ground modifying assembly around this point. Apart from marking levelled and worked ground, it puts severe strain on the assembly's structure. This all happens in a split second, so is difficult for the operator to identify, as they are often looking behind to see where they going.

[0261] The force can be extreme, causing even 40 mm wheel pivots pins to be bent. All manufacturers have grappled with this issue and a solution is a longfelt want. It is not uncommon in the industry to have wheels torn completely off.

[0262] One solution of the present invention is to lower the pivot point of the walking beam as low as possible to get it below the centre of gravity of the walking beam assembly. Ideally the pivot should be below the centre of gravity of the pivoting walking beam assembly. There may be further advantage in some embodiments in placing the beam pivot point below the rotational axis of the wheels, but ground clearance (for various applications of a ground modifying assembly is a practical consideration in calculating the lowest practical pivot point in differing embodiments.

[0263] By lowering the beam pivot point, we can potentially realize several effects: [0264] A walking beam's natural pendulum tendencies in embodiments of the present invention differ from that of the prior art (which has a pivot above the centre of gravity). Thus, when a ground modifying assembly is turned with the wheels raised, or not contacting the ground, the natural action is for the leading wheel to RAISE and the trailing wheel to contact the ground. As this wheel is behind the pivot point, it forms a natural castor action, extending the length to the centre line. This reduces any force to push the wheel into the soft ground. [0265] The angle of attack is significantly reduced, as the pivot is closer to the surface of the ground. Technically, if we placed the pivot at ground level or below, there would be zero angle of attack. Of course we have to leave some room above the ground, but by lowering the pivot height compared to the prior art the angle can be reduced significantly.

[0266] The down side is the walking beam will fall to either side now when raised though the effects of this can be addressed with solutions such as rubber bump stops.

[0267] FIGS. 20 and 21 illustrates a low pivot version of a carriage in a schematic fashion. FIGS. 26 and 27 represent a preferred embodiment. (501) represents the forward drawbar or portion of the ground contouring assembly to which the carriage portion is affixed. For reference, an example of a high pivot walking beam such as previously used in the art, is illustrated in FIG. 14, as well as other figures such as FIG. 5.

[0268] A downward extension (502) provides a suitable mounting point for the carriage pivot portion (506). This carriage pivot (506) connects the extension (502) to the lower extending portion of the carriage body (505) to which the wheel assemblies (504) are attached. The wheel assemblies (504) of this embodiment can rotate about a substantially vertical axis by pivotable attachment (503). Ideally the wheel assemblies are a trailing type assembly in this embodiment, where (in plan) the central wheel pivot is offset from vertical pivot (503).

[0269] The applicant has found that by positioning the carriage pivot (506) below the central pivot of the wheels (504) the pendulum and swinging effects of high mounted pivots (such as in earlier figures) is reduced, minimised, or even eliminated. Hence this arrangement may be applied to suitable embodiments of FIGS. 1 through 18.

[0270] FIGS. 26 and 27 illustrate a working embodiment of a ground modifying assembly (530) with and underslung pivot (506). In FIG. 27 a simple embodiment which might be used on an excavator arm is shown. Here the ground working accessory (520) is a blade, and this faces away from the wheel portiontypically an excavator will use its boom/arm to draw the ground modifying assembly (530) towards it. However it should be appreciated that this ground working accessory (520, 521) may, in other embodiments, be substituted by other body and accessory portions as in other figures of this specificationor in other words, the underslung pivot (506) carriage arrangement may be substituted for the wheeled carriage portions appearing in embodiments illustrated in other figures herein.

[0271] FIG. 26 illustrates how, when the apparatus is lifted from the ground (or travelling over uneven ground) the front carriage portion (503, 504, 505) will tilt to one side of the other (if dangling) or tilt to follow ground contours. Rubber stops (518) may be provided to lessen shock as it meets the maximum rotation limit.

[0272] FIGS. 22 through 24 comprise a different embodiment of a leveller which uses a simpler parallel type linkage arrangement. This arrangement is potentially useful in some embodiments of levellers (ground modifying assemblies), and particularly for excavator mounted levellers. Depending on the size of an excavator (or other vehicle with a movable support arm) there may be a weight restriction on attached accessories which also has a bearing on the maximum reach, maximum angle of inclination of a ground plane on which the excavator/vehicle is working, etc.

[0273] In FIGS. 22 through 25 is shown an alternative embodiment which uses a simpler linkage system which can yield a lighter leveller type assemblypotentially a significant advantage for excavators. There are also some other potentially realisable benefits which can lead to increased usage and field of operation of leveller assemblies. Such potential benefits may include: lower manufacturing costs, lighter weight, simpler control of moving parts.

[0274] We will refer back to FIG. 1, which represents the geometry of the applicant's prior art levelling assembly for comparison. Here the fixed diagonal linkages (6a, b) between the front accessory body portion (3) and the rear body portion (2) effectively prevents sideways lateral movementwhich was considered a desirable attribute for the intended uses of this device. However, now the art and industry needs apparatus with lateral adjustment.

[0275] In another embodiment of the present invention and with reference to the drawings, and by way of example only, there is provided a levelling assembly (see FIG. 22) comprising a front accessory body portion (603), and a rear body portion (602),

the two body portions (602, 603) connected to each other by at least four body connecting linkages (L605, L606, R605, R606),
said body connecting linkages, in plan view, being distributed either side ((L605, L606) and (R605, R606)) of a vertical longitudinal centre-plane (607) bisecting said two body portions (1602, 603),
said body connecting linkages ((L605, L606) and (R605, R606)) including pivotable linkage connections to said body portions (602, 603) to allow, when viewed from the side, the relative elevation to the two body portions (602, 603) to alter.

[0276] The front accessory body portion (603) includes a blade (608) attached to a mouldboard portion (609) and has collectively been referred to as the blade previously in this specification. Side guards (L610 and R610) may be provided or both sides, one side only, omitted, or removably attached as required.

[0277] The rear body portion (602) provides a body structure including a mounting point (612) for one end of an actuator (614) comprising the lateral shift control linkage. A pivotable bush or ball joint type connection may be provided here (612). The other end (615) of the actuator (614) is attached to the front accessory body portion (603) though due to the partially cut away view the mounting attachment point is not fully visible.

[0278] The rear body portion (602) may also include an attached quick hitch mount as required, and as is visible as item (4) in FIG. 1.

[0279] In the side view of FIG. 24 from the left side, we can see the upper (L605) and lower (L606) connecting linkages connected (L705 and L706) to the structure of the body portion (602). FIG. 3 better shows the alternate end pivotable connections (L805 and L806) for the respective linkages (L605 and L606) to the rear structure of the front body portion (603). Referring back to FIG. 2 we can see the preferred substantially parallelogram arrangement of this embodiment between the connecting linkages (L605, L606) and the body portions (602, 603). The arrangement and geometry of the right hand side is typically a mirror replication through the centre plane (607).

[0280] FIG. 25 shows the left (L618) and right (R618) elevation controlling linkages, comprising linear hydraulic actuators. FIG. 2 illustrates the diagonal mounting arrangement (from side view) of left (equivalent to right) elevation controlling linkage (L618), and its connection (L818) near the top of the rear body portion (602) though the connection (L818) to the front body portion (603) is obscured in this figure.

[0281] These elevation controlling linkages (L618, R618) may be placed inwardly (closer to the centre plane (607)) or outwardly of the left and right sets of connection linkages ((L605, L606) and (R605, R606)) as convenient or desired.

[0282] The levelling apparatus may also include an excavator boom arm quick mount (626) if this is a required vehicle mounting option.

[0283] Laser sensor poles may be affixed at mounting points (L628, R628) on the side guards (L610, R610) if required, and sensors (not shown) attached.

[0284] A forward wheel assembly, possibly upwardly folding or retractable may be provided on various embodiments though this may not be required on all embodiments,

[0285] A kerb following wheel assembly may be provided on one or both sides of the front accessory body portion (602) to assist an operator in precision following of an existing structure or feature.

[0286] With general reference to the embodiments of FIGS. 22 through 25, other embodiments are possible. For instance in the applicant's previous levelling apparatus (U.S. Pat. No. 10,323,382) the linkage geometry precluded relative lateral shifting of the body portions in order to achieve rotation about a longitudinal axis. Accordingly this document teaches away from the present invention, as well as there being considerable changes in geometry.

[0287] In preferred embodiments of the general parallel linkage arrangement of FIGS. 22 through 25 there are ideally four connecting linkages. These are typically divided into two sets of two, which are conveniently referred to as left and right linkage sets, and distributed (ideally substantially equidistantly) outwardly of a vertical longitudinal centre plane (within which the levelling assembly's longitudinal axis in use also lies). Typically no connecting point for a connecting linkage is near the centre plane in preferred embodiments.

[0288] When preferred embodiments are view from the side, the two connecting linkages of each set are displaced vertically with respect to each otheri.e. one appears positioned above the other, and in preferred (but not necessarily all) embodiments is vertically displaced one above the other. As (also in preferred embodiments) the general planes of the two body portions are roughly parallel to each other, from the side the arrangement of the two connecting linkages (of a set) with the two body portions form a quadrilateral. This may ideally be a parallelogram but in practice may deviate from this precise geometry, and various contributing elements to this parallelogram may (typically) each fall up to (and including) 20 degrees of this ideal parallelogram.

[0289] In order for there to be relative movement between the body portions we need to have a pivotable connection between same and the connecting linkages. While this may be a connection pivotable about a single axis (suitable for simple more limited embodiments of the present invention with a restricted range of movement), the desired range of movement in preferred embodiments prefers a more multi-axial range of movement such as provided by a ball joint. In practice, a single axis mounted connection with a flexible bush accommodating movement in other directions (such as by bush compression) is often suitabletruck suspension arm/component connections with compressible bushes are one example. At the end of the day, a pivotable connection which allows for the desired relative movements is used.

[0290] The elevation controlling linkages are typically also connected to the body portions with pivotable connections equivalent to the connecting linkages. The elevation controlling linkages are typically actuators, and hydraulically controlled in preferred embodiments. These are typically operated in tandem, though users may operate them differently and in the geometry of the preferred embodiment limited rotation of the two body portions relative to each other is possible by altering the length of the actuators by different amounts. This is useful where the leveller is used to create an incline (e.g. roading etc.) during its operation. Hence preferred embodiments of the present invention can provide lateral and elevational translational movement, as well as longitudinal axis rotational movement, relative between the front and rear body portions.

[0291] Typically an elevation controlling linkage is mounted substantially diagonally in side view, often being connected (in side view) at or near the top of one body portion and at or near the bottom of the other. Variations may exist in practice, though the requirement is to be able to change the relative elevation of one body portion to the other by altering the length of said elevation controlling linkage.

[0292] It should be recognised that it is also possible to substitute linear actuators for one or more of the connecting linkages, so as to provide a greater range of relative conformations between the front and rear body portions, though this does add to the complexity and cost of the resulting apparatus. However, for specialised applications, this may become a viable option.

[0293] Lateral translation control may be provided by a lateral shift control linkage. In simple terms this may be a substantially transverse linear actuator connected at one end to the front accessory body portion, and at the other end to (or an element attached or part of) the rear body portion. Typically, in plan view, one end of the lateral shift control actuator linkage will be connected to one of the body portions at or towards its left side, and the alternate end to the other of the body portion at or towards its left side. While this actuator may be normal to the longitudinal centre plane, in practice it may be at an angle to the transverse so as to take advantage of suitable mounting points on the body portion and/or to avoid obstruction with other parts, portions, or components of the levelling assembly.

[0294] Laser sensor guide poles may be provided on various embodiments, allowing for the mounting of laser guidance sensors and their integration in to optionally provided laser guidance control systems available in the market.

[0295] Various mounting systems may be provided. A typical almost industry standard quick hitch mount (as commonly used on skid-steer loaders) may be provided on various embodiments. Other options include mounting attachments for boom arms such as commonly present on excavator arms. Various options may be implemented according to user need.

[0296] Aspects of the present invention have been described by way of example only and it should be appreciated that modifications and additions may be made thereto without departing from the spirit or scope of the present invention as described herein.

[0297] It should also be understood that the term comprise where used herein is not to be considered to be used in a limiting sense. Accordingly, comprise does not represent nor define an exclusive set of items, but includes the possibility of other components and items being added to the list.

[0298] This specification is also based on the understanding of the inventor regarding the prior art. The prior art description should not be regarded as being authoritative disclosure on the true state of the prior art but rather as referencing considerations brought to the mind and attention of the inventor when developing this invention.