EP4653620A1

EP4653620A1 - Motorgrader

Info

Publication number: EP4653620A1
Application number: EP25176327.2A
Authority: EP
Inventors: Lorenzo MELIS
Original assignee: CNH Industrial Italia SpA
Current assignee: CNH Industrial Italia SpA
Priority date: 2024-05-23
Filing date: 2025-05-14
Publication date: 2025-11-26

Abstract

Motor grader comprising a frame formed by a front portion (FF) hinged to a rear portion (RF), a front axle (FA) associated with the front portion (FF) of the frame, in which the front axle is steerable with respect to the front portion (FF) of the frame, a levelling blade (LB) having an elongated shape, so as to define a longitudinal development axis, associated with the front portion of the frame by means of a support system (TT, HA, PA), the motor grader being characterized by the fact that the support system is configured to perform an operation of overturning the levelling blade around an axis (X) parallel to said development axis for an angle of approximately 180°.

Description

Field of the invention

The present invention relates to the field of motor graders. Hereinafter, grader means a motorgrader.

State of the art

Motorgraders are work vehicles that can be used in agriculture and on construction sites, with reference to figure 1 of the prior art. Generally, graders equipped with tracks are used in the agricultural sector, while wheeled graders are implemented in the construction of buildings and infrastructures.
Motorgraders are generally self-propelled vehicles equipped with two frame portions FF, RF hinged together by a hinge H, in which the rear portion includes a pair of drive axles RA1, RA2 or tracks and the front portion includes a steering axle FA.
The cab CB of the vehicle can be associated with both the front part of the frame and the rear part of the frame. In figure 1, the hinge is shown at the rear of the cabin, but it could also be placed at the front of it.
A structure generally called a "yoke" is connected to the front portion of the frame, in an intermediate position between the front axle and the hinge, to support a levelling blade B or "moldboard blade", whose position is regulated using appropriate actuators HA, PA.
The levelling blade is hinged to a TT fifth wheel, generally called a "turntable" which allows movements around an approximately vertical operating axis.
In the following, "blade" means "levelling blade".
The inclination of the blade can be adjusted using a suitable hydraulic actuator PA generally named as "Blade pitch".
The bade pitch actuator can induce a limited variation in the angle of attack of the blade on the ground.
A vertical actuator HA allows the turntable and with it the levelling blade to be raised and lowered.
The assembly of the turntable and actuators defines a support system for the levelling blade operationally connected to the front FF part of the frame.
In particular, as is known, the front part of the frame is arched to define a cradle in whose convexity it collects the support system of the levelling blade.
To obtain an optimal machining result it may be necessary to carry out several operational steps. Adjusting the position of the blade each time.
A compactor roller can also be adopted in the final stages of the work to compact the soil after levelling it.
To carry out the different operational steps, considerable manoeuvring space is required so that the vehicle can travel, advancing frontally, the same route in alternately opposite directions.
When this manoeuvring space is not available, the operator must raise the levelling blade, go back in reverse, carrying out a non-operational step, lower the blade again and carry out a new operational step.
Evidently, both the manoeuvring operations to turn the vehicle and the non-operational steps consume time and fuel.
Unless specifically excluded in the detailed description that follows, what is described in this chapter is to be considered as an integral part of the detailed description.

Summary of the invention

The purpose of the present invention is to indicate a motor grader capable of reducing the times for carrying out different operating steps on the same portion of land to be levelled.
The basic idea of the present invention is to configure the support system of the levelling blade in such a way as to allow it to rotate approximately 180° around an axis parallel to the development axis of the levelling blade itself.
If the pitch angle were neglected, the rotation would be exactly 180°.
Advantageously, the rotation or overturning of the blade makes possible a front attack configuration, when the vehicle moves forwardly and a rear attack configuration, when the vehicle moves reversely so that in both directions of travel the vehicle is operational, being able to operate on the surface of the ground to be levelled in both directions of travel.
Another advantage deriving from the present invention is the fact that the rotation of the blade around its own development axis or an axis parallel to it, avoids any risk of collision of the blade with a part of the vehicle.
The dependent claims describe preferred variations of the invention, forming an integral part of the present description.

Brief description of the figures

Further objects and advantages of the present invention will be clear from the following detailed description of an example of its implementation (and its variants) and from the attached drawings given purely for explanatory and non-limiting purposes, in which:

figure 1 shows a motor grader according to the prior art;
figures 2 and 4 show two operating configurations of a motor grader according to the present invention, while figure 3 shows a transition condition between the configurations of figures 2 and 4;
figures 5 and 6 show two portions of the vehicle according to figures 2 and 4 respectively;
figures 7 and 8 show examples of a levelling blade support system according to the present invention;
figure 9 shows a detailed perspective view of a support system for a blade according to the present invention.

The same reference numbers and letters in the figures identify the same elements or components or functions.
It should also be noted that the terms "first", "second", "third", "higher", "lower" and the like may be used here to distinguish various elements. These attributes do not imply a spatial, sequential, or hierarchical order for the modified elements unless specifically indicated or inferred from the text.
The elements and characteristics illustrated in the different preferred embodiments, including the drawings, can be combined with each other without departing from the scope of protection of the present application as described below.

Detailed description

The present invention, with reference to figures 2 - 4, shows a motor grader having substantially the same characteristics as a motor grader of the prior art shown in figure 1 with the differences, which are described below.
In particular, the present motor grader differs from the known art in that the support system of the levelling blade allows it to rotate at least 180 degrees with respect to an X axis parallel to the development axis of the levelling blade.
Figure 2 shows the vehicle with the blade arranged in a front attack configuration, marked with the FWD arrow, while Figure 4 shows the same vehicle with the grader blade arranged in a rear attack configuration, marked with the REV arrow. In this second configuration, the vehicle can work the ground moving backwards rather than forwards.
Figure 3 shows a transitional configuration, where the turntable TT is raised using the HA hydraulic actuator. The temporary lifting of the turntable allows the rotation of the blade over the X axis without hitting the ground.
According to the variant of figures 2 - 6, the same actuator that controls the FWD and REV orientation also allows to control the "pitch" attack angle of the blade with respect to the ground to be worked.
According to the solution in figure 7, the blade is hinged to the turntable by means of a connecting rod RD. Therefore, the blade is able to rotate both with respect to the hinge X axis on the turntable and with respect to a second rotation axis Y parallel and distinct from the X axis.
This fact allows to rotate the blade and adjust the angle of attack with respect to two distinct axes and using two different actuation systems. For example, while a first actuator takes care of overturning the blade 180° without position control, a second actuator takes care of fine-tuning the orientation of the blade to manage its angle of attack, or pitch, with respect to the ground.
In figure 7 the pitch actuator (not shown) can operate on a further connecting rod (not shown) fixed with the blade.
Figure 8 shows another variant of the invention, in which the blade is hinged to the connecting rod RB by means of a spindle FS, while the pitch actuator PA is hinged at one end to the connecting rod RB and at another end, opposite to the first, to the blade, so as to form a quadrilateral with the blade, spindle, connecting rod and pitch actuator.
Figure 9 shows a perspective view of a blade support system. The blade is symmetrical in the sense that both edges are operational and the support is made in such a way as to allow the blade to be overturned via the same pitch actuators that allow the adjustment of the angle of attack of the blade with the ground. Evidently, an additional actuator can only deal with the overturning of the blade.
According to a preferred aspect of the invention, the overturning function is managed by CPU processing means configured to calculate an attack angle of the blade as a function of a position of the pitch actuator, perform the overturning of the blade and adjust the pitch actuator, so that the blade assumes the same angle of attack in the reversed configuration.
By reversed configuration it is meant the REV configuration if it was the forward FWD one before the transition and vice versa.
It is worth highlighting that while a traditional blade has only one cutting edge, i.e. the operating one, the lower one, while the other edge, the upper one, is designed for discharging the material removed from the operating edge, according to the present invention, the blade has both cutting edges. In particular it has an elongated shape and convex along the development axis.
Constructive variations to the non-limiting example described are possible, without departing from the scope of protection of the present invention, including all the equivalent embodiments for a person skilled in the art, to the content of the claims.
From the above description, the person skilled in the art is able to realize the object of the invention without introducing further construction details.

Claims

Motor grader comprising a frame formed by a front portion (FF) hinged to a rear portion (RF), a front axle (FA) associated with the front portion (FF) of the frame, in which the front axle is steerable with respect to the front portion (FF) of the frame, a levelling blade (LB) having an elongated shape, so as to define a longitudinal development axis, associated with the front portion of the frame by means of a support system (TT, HA, PA), the motor grader being characterized by the fact that the support system is configured to perform an operation of overturning the levelling blade around an axis (X) parallel to said development axis for an angle of approximately 180°.
Motor grader according to claim 1, wherein said overturning operation allows defining a front pitch angle and a rear pitch angle between the levelling blade and the ground.
Motor grader according to claim 1 or 2, wherein the support system includes an actuator (PA) arranged to perform both said overturning operation and a fine rotation of the levelling blade to vary said front and rear pitch angle.
Motor grader according to claim 1 or 2, wherein the support system comprises a first actuator (PA) arranged to perform said overturning operation, and a second actuator, distinct and separate from said first actuator, to operate a fine rotation of the levelling blade to vary said front and rear pitch angle.
A motor grader according to any of the preceding claims further comprising processing means (CPU) configured to control said support system to perform said overturning operation.
Motor grader according to claim 5, wherein said processing means are configured to perform the following steps in succession:
- acquisition of a current pitch angle of the levelling blade,

- lifting of a turntable (TT) supporting the levelling blade,

- overturning of the levelling blade,

- adjustment of the pitch angle of the levelling blade so as to coincide with said current pitch angle, but in a reversed configuration.
Motor grader according to any of the previous claims, of the wheeled type comprising at least one pair of rear axles (RA1, RA2) of which at least one is propelling, or tracked type.
Method for operating a motor grader according to one of claims 1 - 5, comprising the following steps:
- lifting of a turntable supporting the levelling blade,

- overturning of the levelling blade,

- adjustment of the pitch angle of the levelling blade.
Levelling blade (B) for a motor grader, having an elongated shape along a development axis (X) and convex along the development axis so as to define two edges, in which both edges are cutting edges.