Claims:We claim:

1. An anti-hopping system (200) of a mini grader (100); said anti-hopping system comprises:

(i) a propulsion unit (110) supporting an engine assembly (120) and an operator’s cab (130);

(ii) a grading unit (140) having a front axle (112) with a pair of steerable wheels at the front end thereof; said grading unit (140) fitted with a mould board assembly (180);

(iii) a chassis assembly (160) supporting said propulsion unit (110); said chassis assembly (160) having a fixed middle axle (114) and a swiveling rear axle (116), each axles having a pair of wheels; and

(iv) a mainframe assembly (170) fixed with said grading unit (140) at the front end thereof; and coupled to said chassis assembly (160) at the rear end (162) thereof;

wherein an anti-hopping structure with a pivoting structure having a damping cylinder arrangement (150) is disposed between said grading unit (140) and said chassis assembly (160); and a first oscillation structure is fitted on the front face of said front axle (112) and a second oscillation structure is fitted on the rear face of said rearmost axle (116) of said mini grader (100) to allow said mini grader (100) to effectively negotiate the ground undulations encountered during the movement thereof over any uneven terrain to be worked on thereby.

2. Anti-hopping system (200) as claimed in claim 1; wherein said pivoting structure comprises a pivot pin (166) inserted through brackets (168) longitudinally disposed and fixed at the front end (162) of said chassis assembly (160) and through the brackets (176) longitudinally disposed and fixed at the rear end of said mainframe assembly (170) to control the relative movement between said chassis assembly (160) and mainframe assembly by means of said damping cylinder arrangement (200).

3. Anti-hopping system (200) as claimed in claim 1; wherein said first oscillation structure on said front axle (112) comprises a first swivel pin (175) fixed longitudinally to facilitate the oscillation of said front axle (112) in a transverse plane to negotiate and accommodate any lateral ground undulations encountered by said mini grader (100) during the movement thereof.

4. Anti-hopping system (200) as claimed in claim 3; wherein said first swivel pin (175) is inserted through a bracket (178) disposed transversely and fixed on the front face of said front axle (112).

5. Anti-hopping system (200) as claimed in claim 1; wherein said second oscillation structure comprises a second swivel pin (190) fixed longitudinally to facilitate the oscillation of said rear axle (116) in a transverse plane to negotiate and accommodate any lateral ground undulations encountered by said mini grader (100) during the movement thereof.

6. Anti-hopping system (200) as claimed in claim 5; wherein said second swivel pin (190) is inserted through a bracket (192) disposed transversely and fixed on the rear face of said rear axle (116).

7. Anti-hopping system (200) as claimed in claim 1; said anti-hopping system (150) comprises a damping cylinder arrangement fitted between said chassis assembly (160) and said mainframe assembly (170) to control the relative movement therebetween depending on the weight distribution, the position of said mould board (180) and the power of the engine (120) of said mini grader (100).
8. Anti-hopping system (200) as claimed in claim 7; wherein said damping cylinder arrangement comprises a pair of parallelly disposed hydraulic cylinders (152) with a respective dampening accumulator (154) connected thereto via a hydraulic logic manifold circuit (156).

9. Anti-hopping system as claimed in claim 8; wherein said hydraulic logic manifold circuit (156) comprises:

• a pair of hydraulic accumulators (A1, A2);

• a pair of hydraulic cylinders with two ports (P1, P2; P3, P4) each for said first and second oscillations structures respectively to sense the ground undulations encountered by said mini grader (100) during the movement thereof;

• a pair of dampening blocks (D1; D2) equipped with a respective relief valve (R1; R2); and

• a pair of pilot check valves (V1; V2);

wherein the pressure settings of said dampening blocks (D1; D2) are done depending on the weight distribution, position of said mould board (180); the power of the engine of said mini grader (100).

10. A method of operation of anti-hopping system (200) as claimed in claims 1 to 9, said method comprising the steps of:

(I) pre-charging of said hydraulic logic manifold circuit (156) initially with hydraulic oil filled to a maximum pressure within said cylinders (152);

(II) maintaining said oil pressure within said cylinders (152) according to said pressure settings of said dampening blocks (D1; D2);

(III) controlling said pre-charged oil pressure by means of said relief valves (R1; R2);
(IV) maintaining the position of said mainframe assembly (170) without any relative movement thereof with respect to said chassis assembly (160) by keeping the pressure inside said cylinders (152) to less than said preset oil pressure during the movement of said mini grader (100) by resisting the compressive loads acting thereon;

(V) preventing any leakage of hydraulic oil from said cylinders (152) by means of said pilot operated check valves (V1, V2) during the movement of said mini grader (100); and

(VI) moving said mainframe assembly (170) with respect to said chassis assembly (160) by increasing the pressure above said preset oil pressure and causing the hydraulic oil to flow from said cylinders (152) to said accumulators (154) when the load on said mainframe assembly (170) increases to start applying higher compressive forces on said cylinders (152);

wherein said hydraulic logic manifold circuit (156) is configured in-built in said anti-hopping system (200) to allow the movement of said mainframe assembly (170) after the oil pressure increases above said preset pressure by actuation thereof as an active dampening system.

Digitally Signed.

Dated: this 26th day of March 2020.

(SANJAY KESHARWANI)
APPLICANT’S PATENT AGENT
REGN. No. IN/PA-2043. , Description:FIELD OF INVENTION

The present invention relates to a mini grader used in small construction projects. In particular, the present invention relates to an improved arrangement for reducing / eliminating hopping instability in a mini grader. More particularly, the present invention relates to an improved mini grader with an anti-hopping system to prevent hopping instability due to bounding of the mini grader.

BACKGROUND OF THE INVENTION

Normally, a regular motor grader is used for road construction projects. Such motor grader includes a drivetrain with transmission and drive chains to facilitate absorption of any undulation of the ground being worked on.

Here, the rear axle functions as an independent suspension and the front axle offers oscillations to facilitate the motor grader to cover the landscape with any topography. However, the cost of this motor grader drive train is quite high, and it also requires an independent suspension system. So, using a motor grader for small budget projects, like for rural road constructions, would not be feasible for above-stated reasons.

Therefore, a mini grader can instead be effectively used in such small construction projects, e.g. for rural road construction work, due to allotment of very small capital budget therefor. This obviates the need of deploying a motor grader using costly and complex tandem axles. However, the disadvantage with the mini grader disclosed in the aforesaid main patent application is that it cannot prevent hopping thereof.

This is because a min grader does not have enough weight for efficient power transfer the ground. Power hop occurs when a mini grader operates in dry, loose soils, and lack of moisture causes difficulties in gaining sufficient traction.

Hopping involves uneven bouncing occurring during the operation of a tractor with four-wheel drive and especially in a mini grader. This hopping phenomenon is also observed on operating mini grader under substantial draft load due to the flexing and recoiling of tyre sidewalls, on the mini grader gaining traction.

DISADVANTAGES OF THE PRIOR ART

The conventional mini graders have the following disadvantages:

a) Power hopping of mini graders causes disturbing vibrations being generated during the operation thereof and which are experienced by the mini grader operator.

b) Normally, hopping causes mini grader to bounce over the operational area and if left uncontrolled, may rise substantially over time.

c) Power hopping impairs the operational stability of the mini grader.

d) Hopping creates problems for the mini grader operator to effectively carry out the assigned work and exposes him to tremendous frustration.

e) A mini grader undergoing uncontrolled hopping subjects the mini grader operator to uncomfortable ride as well as serious damage to mini grader.

f) Power hopping also impairs the targeted performance of the mini grader, which substantially reduces the operational productivity and thereby profitability of the mini grader.
Therefore, there is an existing need to an anti-hopping system for a mini grader to overcome the aforesaid disadvantages associated with the conventional mini grader configurations.

In particular, it is necessary provide an anti-hopping system for the mini grader disclosed in the above-referred main patent application, which can reduce/eliminate the power hopping of such mini graders.

OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide an anti-hopping system for mini grader without tandem axles.

Another object of the present invention is to provide an anti-hopping system for mini grader to prevent hopping instability thereof.

Still another object of the present invention is to provide a low-cost anti-hopping system for mini grader.

Still further object of the present invention is to provide anti-hopping system for mini grader to enhance operator’s comfort level and reduce frustration.

A further object of the present invention is to provide anti-hopping system for mini grader to prevent potential damage thereto.

These and other objects and advantages of the present invention will become more apparent from the following description, when read with the accompanying figures of drawing, which are however not intended to limit the scope of the present invention in any way.
SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided an anti-hopping system of a mini grader; comprising:

(i) a propulsion unit supporting an engine assembly and an operator’s cab;

(ii) a grading unit having a front axle with a pair of steerable wheels at the front end thereof; the grading unit fitted with a mould board assembly;

(iii) a chassis assembly supporting the propulsion unit; the chassis assembly having a fixed middle axle and a swiveling rear axle, each axles having a pair of wheels; and

(iv) a mainframe assembly fixed with the grading unit at the front end thereof; and coupled to the chassis assembly at the rear end thereof;

wherein an anti-hopping structure with a pivoting structure having a damping cylinder arrangement is disposed between the grading unit and the chassis assembly; and a first oscillation structure is fitted on the front face of the front axle and a second oscillation structure is fitted on the rear face of the rearmost axle of the mini grader to allow the mini grader to effectively negotiate the ground undulations encountered during the movement thereof over any uneven terrain to be worked on thereby.

Typically, the pivoting structure comprises a pivot pin inserted through brackets longitudinally disposed and fixed at the front end of the chassis assembly and through the brackets longitudinally disposed and fixed at the rear end of the mainframe assembly to control the relative movement between the chassis assembly and mainframe assembly by means of the damping cylinder arrangement.

Typically, the first oscillation structure on the front axle comprises a first swivel pin fixed longitudinally to facilitate the oscillation of the front axle in a transverse plane to negotiate and accommodate any lateral ground undulations encountered by the mini grader during the movement thereof.

Typically, the first swivel pin is inserted through a bracket disposed transversely and fixed on the front face of the front axle.

Typically, the second oscillation structure comprises a second swivel pin fixed longitudinally to facilitate the oscillation of the rear axle in a transverse plane to negotiate and accommodate any lateral ground undulations encountered by the mini grader during the movement thereof.

Typically, the second swivel pin is inserted through a bracket disposed transversely and fixed on the rear face of the rear axle.

Typically, the anti-hopping system comprises a damping cylinder arrangement fitted between the chassis assembly and the mainframe assembly to control the relative movement therebetween depending on the weight distribution, the position of the mould board and the power of the engine of the mini grader.

Typically, the damping cylinder arrangement comprises a pair of parallelly disposed hydraulic cylinders with a respective dampening accumulator connected thereto via a hydraulic logic manifold circuit.

Typically, the hydraulic logic manifold circuit comprises:

• a pair of hydraulic accumulators;

• a pair of hydraulic cylinders with two ports each for the first and second oscillations structures respectively to sense the ground undulations encountered by the mini grader during the movement thereof;

• a pair of dampening blocks equipped with a respective relief valve;

• a pair of pilot check valves;

wherein the pressure settings of the dampening blocks are done depending on the weight distribution, position of the mould board; the power of the engine of the mini grader.

In accordance with the present invention, there is also provided a method of operation of the aforementioned anti-hopping system, comprising the steps of:

(I) pre-charging of the hydraulic logic manifold circuit initially with hydraulic oil filled to a maximum pressure within the cylinders;

(II) maintaining the oil pressure within the cylinders according to the pressure settings of the dampening blocks;

(III) controlling the pre-charged oil pressure by means of the relief valves;
(IV) maintaining the position of the mainframe assembly without any relative movement thereof with respect to the chassis assembly by keeping the pressure inside the cylinders to less than the preset oil pressure during the movement of the mini grader by resisting the compressive loads acting thereon;

(V) preventing any leakage of hydraulic oil from the cylinders by means of the pilot operated check valves during the movement of the mini grader; and

(VI) moving the mainframe assembly with respect to the chassis assembly by increasing the pressure above the preset oil pressure and causing the hydraulic oil to flow from the cylinders to the accumulators when the load on the mainframe assembly increases to start applying higher compressive forces on the cylinders;

wherein the hydraulic logic manifold circuit is configured in-built in the anti-hopping system to allow the movement of the mainframe assembly after the oil pressure increases above the preset pressure by actuation thereof as an active dampening system.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings:

Figure 1a shows a perspective view of the conventional mini grader with three axles and a drive train assembly for compensating for the undulations of the ground by using rear tandem axles.

Figure 1b shows a side-view of the conventional mini grader (shown in the background) equipped with the chassis and the mainframe assembly oscillating about the forward axle (middle axle of the mini grader) of the twin rear tandem axles.

Figure 2 shows a mini grader with three axles fitted with wheels, however without tandem axles and equipped with an anti-hopping system configured in accordance with the present invention.

Figure 3a-3c show the different positions of the mini grader equipped with the new drivetrain mechanism and having vehicle architecture configured in accordance with the present invention with different axles disposed above undulations in ground.

Figure 4a shows a perspective view of the chassis assembly and the mainframe assembly of the mini grader of Figure 2.
Figure 4b shows a detailed side view of the chassis assembly and the mainframe assembly (without grading unit) of the mini grader of Figure 2.

Figure 5 shows a mini grader with three axles fitted with wheels and equipped with an anti-hopping system configured in accordance with the present invention.

Figure 6 shows a close-up view of the hydraulically operated anti-hopping system with a damping cylinder arrangement fitted between the chassis assembly and mainframe assembly of the mini grader of Fig. 2.

Figure 7a shows the hydraulic logic manifold for the hydraulic cylinder of the anti-hopping system of Figure 6.

Figure 7b shows the hydraulic logic manifold circuit of the hydraulic logic manifold shown in Figure 7a.

DETALED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Figure 1a shows a perspective view of the conventional mini grader 10 with three axles, a front axle 12 and a pair of tandem axles 14, 16 at the rear and with a blade 18 in between the front axle 12 and middle axle 14. The mini grader 10 was equipped with a drive train assembly for operating the chain drive for compensating for the undulations of the ground by means of this tandem axle construction. The tandem axles fitted with wheels 14, 16 to support the engine 20 and operator’s cab/canopy 30. The tandem axles fitted with wheels 14, 16 are located close to each other for imparting a greater weight bearing capacity than a single axle at the rear to support much heavier engine 20 and operator’s cab 30.

Figure 1b shows a schematic view of the chassis and the mainframe assembly of the conventional mini grader 10 (shown in the background) oscillating about the middle axle or the forward axle of the twin rear tandem axles. The blade 80 is shown disposed between the front axle 12 and the forward axle 14 of the tandem axles. Here, the rear tandem axles jointly act as an independent suspension and the front axle can oscillate about this middle axle (shown by anticlockwise arrow C) for allowing the mini grader 10 to travel on any topography. The centrally pivoted construction of the drive chain mechanism enables it to absorb any undulation of the ground by facilitating the movement of the wheels in up and down direction and independent of each other and thereby allows the mini grader 10 to travel on any topography. Thick red double-sided arrows depict the movement of the tandem axles 14, 16. However, the power hopping phenomenon is observed in mini grader (Fig. 5), which often causes excessive vibrations generated during the operation and disturbing bouncing effects are experienced by the operator.

Figure 2 shows a mini grader 100 with the new drivetrain layout and vehicle architecture configured in accordance with the present invention. This drivetrain layout and vehicle architecture does not require tandem axles. The encircled portion A represents chassis assembly mounted with a propulsion unit 110 for traction generation and consists of a front axle 112, a middle axle 114, a rear axle 116 (both not tandem axles) fitted with wheels. The axles 114, 116 supports the engine assembly 120 and operator’s cab/canopy 130 and these axles 114, 116 are located substantially closer to each other for imparting a greater weight bearing capacity (than a lighter single axle configuration at the rear) and thereby to support much heavier engine 120 and operator’s cab 130. Here, it is possible for mini grader 100 to absorb ground undulations very effectively even without the tandem rear axles. Similarly, the encircled portion B represents a grading unit 140 with a mould board assembly/blade 180 disposed between the front axle 112 and the middle axle 114.The chassis assembly 160 is coupled to an improved mainframe assembly 170 for a pivoting connection thereof to grading unit 140. Here as well, the hopping is observed in mini grader due to vibrations generated during the operation and mini grader 100 experiences bouncing thereof in directions H1-H2 shown by double arrow. Therefore, an anti-hopping arrangement 200 is configured of a combination of pivoting and oscillating structures provided between grading unit 140 and chassis assembly 160.

Figure 3a shows the position of the mini grader 100 equipped with the drivetrain mechanism and having vehicle architecture configured in accordance with the present invention is travelling in direction Tr. So, when its front axle wheels 112 pass over a substantial undulation U1 present in the ground surface GL, the rear axle wheels 116 are resting on the ground level GL and the front axle wheels 112 are positioned raised on this undulation U1 and therefore, the middle axle wheels 114 remain off the touching position of the ground GL. In fact, mini grader is travelling in the direction Tr not along the ground level GL, but along the inclined level AL1.

Figure 3b shows the mini grader 100, when its middle axle wheels 114 pass over a substantial undulation U2 present in the ground surface GL. Here, the front axle wheels 112 and rear axle wheels 116 are resting on the ground level GL and the middle axle wheels 114 are positioned raised on this undulation U2 and therefore, the middle axle wheels 114 remain off the touching position of the ground GL. Although travelling in the direction Tr, the mini grader 100 is not positioned exactly along the ground level GL but is inclined thereto.

Figure 3c shows the mini grader 100, when its rear axle wheels 116 pass over a substantial undulation U3 present in the ground surface GL. Here, the front axle wheels 112 and middle axle wheels 114 are resting on the ground level GL and the rear axle wheels 116 are positioned raised on this undulation U3 and therefore, the rear axle wheels 116 remain off the touching position of the ground GL. In fact, the mini grader 100 is travelling in the direction Tr, not along the ground level GL, but along the inclined level AL2.

Figure 4a shows a perspective view of the superstructure of the mini grader 100 including chassis assembly 160 and mainframe assembly 170 of the mini grader 100 of Fig. 3. A pivoting structure including a transversely inserted pivot pin 166 through brackets 176 fixed at the rear end of mainframe assembly 170 (marked encircled as C) and through brackets 168 fixed at the front end 162 of the chassis assembly 160 is provided for neutralizing hopping experienced by the mini grader 100 during movement thereof on ground GL having undulations in different directions. This pivoting structure is described in more details with reference to Figure 6 below. A first oscillation structure 175 (encircled as D) is provided at the front end 172 of the mainframe assembly 170 and a second oscillation structure 190 (marked encircled as E) is provided at the rear end 164 of the chassis assembly 160.

Figure 4b shows a detailed side view of the chassis assembly 160 and the mainframe assembly 170 (without grading unit 140) of the mini grader 100 of Figure 4a. The pivoting structure includes a pivot pin 166 inserted through the front end 162 of chassis assembly fixed with brackets 168 on either side thereof. The pivot pin 166 also passes through brackets 176 fixed on the rear end of the mainframe assembly 170. So, pivot pin 166 functions as a pivot point between the chassis assembly 160 and mainframe assembly 170 for accommodating ground undulations encountered during movement of mini grader 100 over any uneven terrain. The first oscillation structure includes a first swivel pin 175 fixed longitudinally in a transverse bracket 178 fitted on the front face of front axle 112. This swivel pin 175functions as an oscillation pivot for swiveling of front axle 112 with respect to the direction of movement of mini grader 100. The second oscillation structure includes a second swivel pin 190 fixed longitudinally in a transverse bracket 192 fitted on the rear face of rear axle 116. This second swivel pin 190 functions as an oscillation pivot for swiveling of the rear axle 116 with respect to the direction of movement of mini grader 100. Therefore, the combination of the front axle swivel pin 175, middle axle pivoting structure including a pivot pin 166 and rear axle swivel pin 190 form the key anti-hopping structures of the present invention. With this new vehicle architecture, mini grader 100 can handle any ground undulation encountered during the movement thereof over any topography of terrain by allowing itself to orient front axle 112 and rear axle 116 to take a common ground plane GL, whereas middle axle 114 remains displaced from the ground level AL1, GL, AL2 (see Figures 4a to 4c) to accommodate any undulations (U1, U2, U3) present in the ground topography during the movement of mini grader 100.

Figure 5 shows the mini grader 100 with three axles fitted with wheels and equipped with an anti-hopping system (AH)200 configured in accordance with the present invention. The location of the pivoting structure of this anti-hopping system AH is encircled. Here, the power hopping of mini grader 100 is occurring in directions H1-H2 shown by double arrow and which are successfully absorbed by pivoting structure discussed in more details with reference to Fig. 6 below.

Figure 6 shows a close-up view of the hydraulically operated pivoting structure of the anti-hopping system 200 with a damping cylinder arrangement 150 fitted between chassis assembly 160 and mainframe assembly 170 of mini grader 100 of Fig. 2.

Figure 7a shows the hydraulic logic manifold circuit 156 for the hydraulic cylinder arrangement 150 of the anti-hopping system AH of Figure 6a. It includes a pair of parallelly disposed hydraulic cylinders 152 with a respective pair of dampening accumulators 154 connected thereto via a hydraulic logic manifold circuit 156.

Figure 7b shows the hydraulic logic manifold circuit of the hydraulic logic manifold shown in Figure 7a. The hydraulic logic manifold circuit includes accumulators A1, A2; two hydraulic cylinders with ports P1, P2; P3, P4; two relief valves R1, R2 on the hopping dampening blocks D1, D2; and two parallelly disposed pilot check valves V1, V2 respectively. The pressure setting on these dampening blocks D1, D2 depend on multiple factors like weight distribution, position of the ground engagement tool, engine power etc. and must be optimized for a grader. The optimized pressure setting can then be preset into the dampening blocks D1, D2.

WORKING OF THE INVENTION:

The detailed function of the hydraulic logic manifold circuit 156 of the anti-hopping system 200 (Fig. 7b) or active dampening system for reducing the bouncing or hopping of the mini grader 100 is as follows:

1) Initially pre-charging of the hydraulic circuit with hydraulic oil filled with a maximum pressure in the range of the optimized pressure inside the cylinders 152.

2) This pre-charge pressure is controlled by relief valves R1, R2.

3) During operation of mini grader, the compressive loads acting on the cylinders 152 is resisted by these cylinders till the pressure inside the cylinders 152 is less than the optimized pressure to help in maintaining the position of the mainframe assembly 170 without any relative movement thereof with respect to chassis assembly 160.

4) Pilot operated check valves V1, V2 help in preventing any leakage of hydraulic oil from the cylinders 152 during mini grader operation.

5) When the load on mainframe assembly 170 increases to such a level that higher compressive forces start acting on the cylinders 152, the pressure increases above the optimized pressure and this causes hydraulic oil to flow from the cylinders 210 to the accumulators 154. This allows the mainframe assembly 170 to move with respect to the chassis assembly 160.

6) In short, the hydraulic logic is in-built in the anti-hopping system 200 configured in accordance with the present invention for allowing the movement of the mainframe assembly 170 after the pressure increases above the optimized pressure. hence this anti-hopping system 200 is also called as an active dampening system.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The mini grader with the anti-hopping system or an active hopping dampening system configured in accordance with the present invention has the following technical and economic advantages:

1. Combination of rigidity during operations and flexibility while tackling obstacles.

2. Dampens and dynamically stabilizes the system in case of power hop.
3. Lower number of passes required to complete the job and hence higher productivity.

4. Operator feel is more like a conventional grader than a mini grader.

5. Higher product CSI as a result of points 1-4 which can lead to higher sales volume.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.
It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. The description provided herein is purely by way of example and illustration.

The various features and advantageous details are explained with reference to this non-limiting embodiment in the above description in accordance with the present invention. The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification.

Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

Although the embodiments presented in this disclosure have been described in terms of its preferred embodiments, a person skilled in the art may make innumerable changes, variations, modifications, alterations and/or integrations in terms of materials and method used to configure, manufacture and assemble various constituents, components, subassemblies and assemblies, in terms of their size, shapes, orientations and interrelationships without departing from the scope and spirit of the present invention.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention.

While considerable emphasis has been placed on the specific features of the preferred embodiment described here, it will be appreciated that many additional features can be added and that many changes can be made in the preferred embodiments without departing from the principles of the invention.

LIST OF REFERENCE NUMERALS

10 Conventional mini grader

12 Front axle
14, 16 Tandem axles
18 Blade
20 Engine
30 Operator’s cab/canopy

100 Mini grader with anti-hopping system according to the
present invention

110 Propulsion unit
112 Steerable front axle
114 Fixed middle axle
116 Fixed rear axle
120 Engine assembly
130 Operator’s cab/canopy
140 Grading unit (encircled B)
150 Damping cylinder arrangement
152 Hydraulic cylinders
154 Dampening accumulators
156 Hydraulic logic manifold circuit
160 Chassis assembly
162 Front end-chassis assembly
164 Rear end of chassis assembly
166 Pivot pin for mainframe assembly
168 Brackets on chassis assembly
170 Mainframe assembly
172 Front end of mainframe assembly
174 Rear end of mainframe assembly
175 Front axle swivel pin
176 Brackets on mainframe assembly
178 First transverse bracket
180 Mould board assembly/blade
190 Oscillation structure
192 Second transverse bracket
200 Anti-hopping system (AH) - hydraulically operated

AL1 Inclined level
GL Ground level
A1, A2 Accumulators of hydraulic cylinders
H1-H2 Mini grader bouncing directions (double arrow)
P1, P2 Ports for first hydraulic cylinder 210
P3, P4 Ports for second hydraulic cylinder 210
R1, R2 Relief valves on hopping dampening blocks
Tr Mini grader travelling direction
U1, U2, U3 Undulations on ground
V1, V2 Check valves